Here are the measurements your asked for. These are + or - a 1/16thdue to old eyes.
Main sail = 51 3/4 ( the backstay) and at50 7/8 (mast line) and at the" The foot of a sail" orbase 13 1/2" (wide)
Jib = 39 1/4" forestay line and 35 7/8" mast side and the base 12 7/8" wide
Just saw your post. There is more active forum for RC Sailboats at rcgroups.com
Might get a quicker response there.
Windchaser
Attached a sail diagrahm and the Seawind installation manual - maybe of interest