First, I'd rank the players, then note which ones will be kept. I wouldn't automatically say the 27th player kept is worth more than the #1 pick- it depends on who's kept. If a bunch of potential 1st rounders are gonna be kept, that'll impact the value of your 1st round pick more than if just sleepers'll be kept.
"When I read about the evils of drinking, I gave up reading." - Henny Youngman
I want a prehensile sucker tail, and I don't want to wait fifty million years.