if the rudder is tight in the casting, can you just not tighten the nut? when i replaced my rudders with EPO2's i barely tightened the nuts, so that i can still spin the bolt so there is no pressure squeezing the rudder from the nut. as long as the bolt is through the nylon insert it will be fine.
I wouldn't take that approach; you are relying on the stiffness of the casting ears to hold the rudder. The rudder forces will flex the ears apart until the bolt starts to come into play, which represents a loss of overall stiffness. I would make the bolt tight enough that the ears cannot flex apart any farther. To me, that means tight enough that the bolt doesn't spin.
'00 H16 #104691 - '78 H16 #32692 ex-rental - Old Holsclaw trailerMy Hobie 16 pages