You have the sizes correct. The actual thickness of the ribs are mm sizes that closely correspond to imperial dimensions. The center rib W1A is 3mm but 1/8 can be used. W1, 3 & 6 are 5mm where 3/16 will work. The remaining ribs are 2mm thick where 3/32 can be used. Are you planning on adding flaps?
Last edited by Kelsey_B; 10-15-2020 at 08:18 PM.