That's going to be tough, Don. It is a nightmare in full size because of the reverse curves involved. You might be able to mask the wing/fuselage joint and then lay in putty which you sculpt to the final contours. This becomes a vac-form master. If our (EAA's) ST is anywhere similar, the bottom fairing is essentially flat, the top ones have all the curves. I use this technique with foam often on full-size to develop a pattern for forming bucks when I can't have the airplane handy to the shop.