A thin section like your current drop is greatly preferred for reasons of drag, your suggested options look to me like a reduction in performance. The problem you have currently looks like a poor pivot pin design. What you want is for the drop blade to be very flat on the side that contacts the rudder, and for the rudder at that same point to be very flat. Then you want a pivot bolt with the least amount of clearance possible.
I'd buy a sheet of Nylatron from McMaster Carr, cheap and self lubricating, and make a large (6" diameter) washer out of that. Put a large diameter stainless fender washer on the outside with a Nylatron washer about 2" dia. under it. This will stop the electrolysis between the washer and the aluminum blade. On the other side of the rudder use a large stainless fender washer, and double nuts to allow you to adjust the clearance and lock it. Adjust it until you feel drag at some point in the blade travel, then back it off about 1/4 turn and lock down the second nut.
You'll have no bang and it'll work smoothly. GO SAILING!
Gary H. Lucas