Ken,

From what I've read in the kit building forum, it sounds like that the 4* 40 and the 4* 60 use the same basic wing design, with 2 differences.

1) The 60 size plans call for dual aileron servos stock, so the wings are already designed to accomodate them

2) The 60 size plans call for diagonal bracing between each wing rib. The 4* 40 (and the 4* 120 for that matter) do not use these diagonal braces. This is because the person who designed the 4* 60 did not design the 40 or the 120.

That's my understanding anyway...take it for what it's worth.