RE: topflite P-47 questions (60 size)
Mine is just under 13lbs (glassed and fully detailed), and is marginal on a ST75. I would go no less than the ST90 if you're glassing it, but would personally lean towards a FS of 1.20 size. The Magnum is probably too small if you're glassing it.
Watch the weight in the tail too - keep EVERYTHING as far forwards as possible, to avoid excess nose weight.
Cam