The Scottish prospects, who were both medallists at last year's world under-23 championships, will make their senior Great Britain debuts in the event, their final tune-up race ahead of the Commonwealth Games.
It marks a return for Austin after almost six months out as a result of injury, while Sheldon vaulted into the world's top 20 with a series of high-class showings on the world circuit. That has since provided an inspiration for Austin and he is optimistic of making a similar leap.
"It's good to be training with him and then see him go and do well in a race," said the 20-year-old. "It backs up the belief that what I'm doing is right. I just want to get a solid performance and see what I can do.
"The last while's been very frustrating. It's not so much that I've not been racing. It's knowing that you're not ready to race. That's tough. But over the past couple of weeks, I've felt ready to go and be back in the mix."
With David McNamee confirming his own comeback from injury, the Scots make up half the GB squad with Olympic champion Alistair Brownlee bidding to emerge from a minor slump by taking the title. The event will provide a barometer for the months ahead and Austin is relishing the test.
"It will be a similar standard to what the Commonwealth Games will be," said the Scot, who may race in the relay tomorrow too. "It's a tough course and a hard race, especially with Alistair doing it. There might be a role for me there, in the way I like to race. It fits in with the team."
Meanwhile, McNamee believes the Championship can push him closer to his best following the bike crash in March which left him on the sidelines. "My arm is getting stronger, which helps with the swimming."