Pete,
Nice looking racer! I hope you have a lot of fun with it.
The big wheel should be great for grass, or pavement that is on the rough side. The wire gear may be more forgiving for pilot technique on hard landings. Be sure to retain the "magic location" of the wheel contact point 15 degrees ahead of the measured CG. This allows the pilot his best shot at landing and getting into the pits cleanly without bouncing it around in the pitman's face. (I always got the vague idea that they don't like that--at least mine always chewed me out for doing that....) On the other hand, if you are racing on grass, it may have to go farther forward. I don't have any advice on that because we have no grass fields out here. Well, we have one gopher patch, but no one can land anything on that.
I suspect that the initial noseheavy condition results from a fuse blank that uses "stunt wood" and perhaps no glass reinforcement? The other changes that you listed would likely have made the nose lighter than the prototype. For example, the full aluminum doubler/gear leg has got to be heavier than the plywood replacement. The two prototypes used firm balsa (I probably have the measured weights somewhere if that would help) that was probably around 10 lb/ft^3 stock. The fuselage was fiberglassed with one layer of .058 oz/yd^2 that was pressed, so very little epoxy. All covered with one coat of clear epoxy paint. Similar treatment for the stabilizer. So not typical sport or stunt construction, but fairly typical of a racer. Yet the overall weights are comparable. Hmmm. If you used lighter wood and no glass, be sure your pitman knows to nose-catch and not wing catch.... And let us know how your stretch fuse, small tail version flies. My second prototype also had the small tail, and does not suffer from any reduction in groove or maneuverability.
A comment on fuel tanks: you will probably not need/want a full 2 oz tank if you are racing with an OS FP. It means your pitman will have to short tank, which takes extra skill and a bit of luck. (A "count of three" squeeze on the filler bottle on the first and second tanks, and topped off for the last.) We raced my ShyFox earlier this month with a new pitman, and we got in three practice flights before the race. He really lucked out--we had one extra lap at the end of the race when the engine died! Depending on your field elevation and the humidity level, you might get 60-70 laps out of a full 2 oz.
I like the logo on the rudder. I might add one to mine to remind me which way the plane should be going!
Good luck, and please let us know how yours flies!!!
Dave "McSlow" Hull