There are some little gaps at aft end and fwd face, but I'm going to cover these with fiberglass so no problem. There is the rumor that using fiberglass on these will eventually crack, but I see other builders before me have done it and I haven't heard of cracking from them. So onward.
Then I drilled all the holes, first 1/32 then to 1/8.
Then per drawing I dimpled the rudder aluminum for the flush head pulled rivets