I have one of those kits, have seen several of them finished and flown, and I don't think there is anything common between that model and any other SIG kit. It's not as big as the Chipmunk, and doesn't have the same leading edge sweep either, it looks to me. Everything else is entirely different. Todd Lee had one of those I remember seeing fly. Like any model, building it straight and reasonable in weight is important. The cowling isn't that heavy and eases construction, and you may just need the nose weight depending on engine used. The scale version you speak of was probably Mike Gretz. I think he did both a C/L and R/C scale version in his time, or it may have been Maxey Hester. I would have to consult the old SIG catalogs and magazines of the time to be real sure. Look up hi biography at the Hall of Fame site here on the list and at the AMA and that will help with the time line. It might notbe one of the most winning designs ever produced, but is one I always looked at when wishing for a kit, but the Chipmunk was there also and it won out!
Type at you later,
Dan McEntee