If you are going to be racking to serving kegs under pressure, there is some good info Dean Palmer's site:
Thanks for the link! Seeing that I generally brew 1/2 batches I was thinking that a 5-gallon corny keg would make for a great primary fermenter. This way I could brew my lagers under pressure, too.
Man, I don't even have beer in my kegs yet, but the money sink keeps opening wider. Could be worse things to spend my money on, I guess. At least it's not meth...
Yes, kegs definitely do make great fermenters for smaller batches. I brew 4 gallon batches in 5 gallon low profile kegs and rack to serving keg under pressure. I love it. I just bent the dip tubes up a couple inches off the bottom so I wouldn't pull all the yeast out of there I might want to harvest. This way, I don't have to worry about hops clogging up the flow.
The thing I'd worry about with racking 2.5 gallons to a 2.5 gallon keg, is maybe having a little more than you thought you had and over filling the serving keg.
I really like doing it this way because I can close the lid with my starsan in the keg and tip the keg upside down to make sure the lid is sealed before racking beer into it.
You won't regret it, dude!