On revision 6.1 of the wing manual on page 4 it says to use 25x 993 (4.8x10mm) on the rear spar double/triple plates. Later when attaching ribs 1-5 to the rear spar it calls for using 991 (4.8x15mm) and 994 (4.0x12mm) rivets. After looking at the rivets more closely they didn't look like they had enough material on the back. Before attaching the rear upper skin support channel, which would make changing these rivets difficult, sent factory a clarification question. They responded that the wing manual instructions were incorrect and that it does need to be 4.8x15mm length rivets. Had to drill out 20 4.8x10mm rivets and replace with 20 4.8x15mm. Before and after pics attached.