Finally got back to the rudder. The original blocks I cut were ok but the 2" holes were a little bigger than 2"... so I cut new blocks and cut new 2" holes. These turned out much better and more snug. I drilled the attachment holes and then clamped them to my worktable to drill holes in the rudder tube using the 3"blocks as guides. The AN4-40 bolts fit perfectly. Next take it all apart and put it back together. This involves painting the metal parts, varnishing the wood and gluing the ribs to the blocks. After that the vertical fwd and aft pieces will be cut and fitted.