Hi Dick,
I dabble in indoor rubber and have flown outdoor rubber extensively (mostly F1B), but for the last few years I have been flying mostly electric pylon racers (R/C). Odd mix, I know. I've been building and flying models for about 25 years... and I'm only 29. Guess that makes me an addict.

I have an electric 3D plane and, while it's not super-light, I do fly it with a rather aft CG of about 35%. This CG would make a lot of R/C planes "unflyable," but the point is that with R/C we have active control. CG and stability still matter, but we get to act as the avionics computer which is keeping the thing going the right direction. So in this regard we are in complete agreement. If the thing is slow and light (and you have R/C), then there is a lot more lattitude in CG placement. Speed things up a bit, like in my 170MPH+ F5D racers, and CG placement is a little more critical.

-David