The dossier, produced by a working group led by senior police officers, proposes an immediate loss of 550 civilian jobs, followed by another £74m of redundancies and early retirements.
The breakdown of cuts also shows police officers are facing a potential £26m raid on their terms and conditions.
In June, MSPs passed legislation to replace the country's eight regional forces with a single Police Service of Scotland. Supporters of the new force, which will be up and running by April, believe the body can save £1.7 billion over 15 years without cutting the number of police officers.
Stephen House, the top officer at Strathclyde Police who was unveiled on Wednesday as the chief constable of the new single force, immediately warned 3000 civilian jobs could go as a result of the merger.
However, the Sunday Herald can reveal a much fuller account of where the axe will fall.
As House was unveiled as chief constable, the body responsible for ensuring a smooth transition to a single force produced a detailed cuts blueprint.
The Police Reform Board, comprised of chief constables and Scottish Government officials, sent the figures to a sub-group set up by Justice Secretary Kenny MacAskill for scrutiny.
The spreadsheet of cuts is broken down into 41 categories and makes grim reading for staff working in law enforcement.
According to the figures, the original "business case" forecast cuts of about £243.7m by 2016. In the new estimate, the total figure has jumped by nearly 25% to £300m.
The document makes clear that deep cuts are expected of the existing eight forces ahead of their abolition in April. To this end, £11.2m has been identified in redundancy costs to "remove" up to 550 civilian staff within months.
The spreadsheet notes that the 550 figure is a "prudent" estimate. It says "we will seek to increase this number based on the interest shown" from staff seeking redundancy.
Although these job losses will not include police officers, they are likely to affect key employees such as forensic staff, fingerprint specialists, scene-of-crime officials and those working in control rooms.
However, the 550 job losses is mild in comparison to the cuts plan for between 2013 and 2016.
According to the dossier, the new Police Service of Scotland could spend £74.3m on redundancy and early retirement costs for civilian staff in this period.
About £2.6m of this has been allocated for "releasing" 67 human resources employees.
In addition, £1.6m has been earmarked for axeing 50 finance jobs and £1.8m for 48 "procurement, fleet and estates" staff.
The plan also forecasts spending more than £13m shedding 50% of all "front counter staff" and police community and support officers (PCSOs), while another £7m has been pencilled in to get rid of 131 clerical staff over three years – again, about 50% of the total number.
Nearly 330 jobs in "corporate services", which are defined as legal services, strategic planning and communications, have a £22m redundancy bill attached to them.
Civilian staff who survive the cull may also be worse off. The reform board has identified nearly £16m of savings from standardising the terms and conditions of police staff.
However, it is not just civilian staff who will bear the brunt of the cuts. The spreadsheet flagged up a near £27m saving from a "potential buyout" of police officers' terms and conditions.
However, the document noted this would require "investment to deliver", which could imply giving lump sums to officers in exchange for special payments being withdrawn.
Other proposed cuts include saving £19.5m on ove rtime, £32m on procurement, nearly £8m on existing police boards, and £6m from the ill-health retirement budget.
Trades unions believe the focus on culling civilian staff is a result of the SNP government's desire to protect police officer numbers.
However, according to the dossier, the redundant clerical posts will be filled by "police officers performing basic administrative duties themselves", while the 94 PCSO roles earmarked to go will also be fulfilled by officers.
The cuts package confirms remarks made by House last week on the financial challenges facing the new service.
Although he did not put an exact figure on the level of cuts anticipated, House said "many, many hundreds" of support staff could go, adding: "It's difficult to be precise at this moment in time, because calculations are still being made and it depends on a lot of different factors.
"I would stress that the plan and the expectation is that much of this will happen through voluntary redundancies and early retirement packages."
Gerry Crawley, Unison's lead officer for police in Scotland, said: "If these figures are true, then they amount to a dramatic cut to the police service, and Unison will not accept these cuts. It has to be pointed out that best value, which is one of the key elements of the single force, will not be met by these plan. The cost of replacing support staff with police officers will be horrendous."
Scottish Liberal Democrat leader Willie Rennie MSP said: "These cuts are even worse than we feared and what was set out in the outline business case. The costly upheaval of centralising our local police forces will have a big impact on the effectiveness of the police.
"It is vital support staff that are to pay the price for the SNP's costly reorganisation. For years we have worked to create police forces with the right level of support staff to help our front-line officers do their jobs. The SNP are reversing that good work to pay for their obsession with centralising control. The Justice Secretary must come before Parliament to explain himself."
Lewis Macdonald, Labour's shadow justice secretary, said: "The loss of police staff, especially in front counters and in custody suites, shows it is simply not credible for the SNP to claim they are putting extra police officers on the streets. This is evidence that Kenny MacAskill is now creating hundreds of backroom bobbies – sitting behind desks instead of being out on our streets.
"MacAskill and Stephen House need to come to Holyrood urgently to clarify what is going to happen to our police force in the years ahead."
A Scottish Government spokesman said: "We have protected – and will continue to protect – frontline police numbers, and the 1000 extra officers we have delivered which have helped reduce crime to a 37-year low, while the fear of crime has also fallen. We have also given a commitment to no compulsory redundancies among police support staff.
"Police reform provides a unique opportunity to improve services. The new service will eliminate duplication by working more effectively and efficiently, saving £1.7bn over 15 years and supporting a single chief constable and one senior management team.
"It will be for the new chief constable and the Scottish Police Authority to determine the balance between police officers and police staff in the new service."