One nice thing about the Tioprare is the amount of room in the fuselage to move stuff around to get the balance. My Tioprare has a painted fuse and MonoKoted tail and wing. With Tri gear retracts and a piped OS 61 pumper mounted on a flex mount the balance is right on with a 1600mah NiCd pack up front over the fuel tank. The OS61 pumper is pretty heavy and I expect that you should be able to do tri gear retracts with the YS and put the battery further back in the fuselage. There is also plenty of room to move the firewall back for the YS installation and easily have room for the nose gear. Don’t forget that removing the nose gear doesn’t help the balance very much when you have to move the weight of the main gear from behind the CG to way out in front of the CG.

Here’s a link to my Tiporare info that shows the layout http://www.rcuniverse.com/forum/m_2827386/tm.htm

Is W-K Hobbies, the hobby shop that was in a southern suburb of Dayton, OH, Miamisburg? I remember hanging out there in the late 70s and early 80s and seeing all the fiberglass molds. I think the owners name was Bill?