I went 25" on my last barrel. I agree that 600 is a touch high. Douglas barrels are usually easy to find. I know a few smiths that don't use Douglas barrels anymore, but thats just because they had beefs with service. Don't forget about Cascade Armory. They are close, and I have been happy with mine. I have one on a bench gun, and it shoots little round groups at 200 yds. The higher end brand name barrels seem to always have a long wait. Nothing wrong with Lilja either.....I went with one on a 338wm,and it shoots great.
Good luck! I hope you end up with a tack driver..