I use the sulivans and really like them. I have found that bigger is better though. The "smaller ones" just have lighter wire for the spring and axel. Go with the biggest one as the physical size of the mount is the same. If your rudder doesnt protrude to the under side of the fuselage though, you are going to have to come up with a method to steer the tailwheel differnt that what is shown with the package instructions.

For the mains, I am a huge fan of the Dubro Heavy duty composite. They take the punishment of hard landings with complaint. They are light enough for a 40 size trainer and I have put them on a 60 size bipe that weighs almost 10 lbs. vary the wheel size to get the ground height you need.

Make sure the main axels are under or just barely ahead of the LE of the wing when the wing cord is level with the ground. To far forward and it is vey hard to steer on the ground. To far back and you end up nosing over.

Attach a photo of the plane and we can give better instructions on how to accomplish a steerable tailwheel.

Don