My project gun for the year is a 700 SPS Varmint in 7mm08. Factory barrel length is 26". Right now it is at the Gunsmiths' shop being cut down to 20". I considered 18" and marked the barrel at both lengths, asked the same questions down in the Smithy and Loading forums too. 20" is plenty short to be maneuverable in the stands that I hunt or for most instances IMO. Plus I felt like the balance would be a little better than the 18".
I have the same gun where I kept the 26" length and it'll flat out shoot. It's just long for a tight stand and unwieldy when trying to get on those animals that don't cooperate, hence version 2. Weight doesn't matter that much to me since our style of hunting is mostly stands and blinds and I like a thicker profile barrel. I have a similar set-up to the build in a .308 Savage 10 PC, just don't like the .308 as much as the 7mm08 for deer hunting in my area.
Good luck on the decision, post up some numbers when you decide what to do. I'd be interested to see what performance was like since I could always cut down again.
I think I'm going to have a lot of fun experimenting with different loads and bullet weights on this one. Hopefully the current load will shoot well in it too because it is absolutely devastating on deer.