RCRICKB-

I just finished an USL 120 and thought I would give you my input. I used a rather heavy engine....the OS 120 SP. This is their supercharged version, and according to rcu's data it is approximately 2 oz. lighter than the Saito 220. I ended up cutting a hatch in the bottom of the fuse, just in front of the horizontal stabilizer....this allowed me to move the battery as far back as possible. If I want to move the cg aft, I will need to add tail weight as I don't have anything else to move.
I think you will end up having to add tail weight in order to balance your plane, but if you move your battery rearward like I did it probably won't be a significant amount of weight...
One other option, which I'm sure you have seen on rcu is to move your ele & rud servos to the rear.....

As for the plane itself.....it rocks!!! I think a stick is one of the best flying birds made, and the 120 size just takes it to the next level.....it's big enough to actually "fly" maneuvers rather than just be "yanked" through them.

Good luck with your project!!!!

Jeff