N16FW

Sadly my plane isn't a Cozy, or an EZ. I added winglet rudders to a Defiant, and I don't remember what plans (if any) I used, but there is no hook at the back of the spring tube. The spring disappears into a block of wood at the back of the tube. I guess I am forced to try plan "A", making a holesaw

I like that plan even better

Is there a way to replace the rudder springs, short of putting a hole in the winglet? Is there a rust resistant replacement?