I replaced the old lousy door latches in my 54' 180 back in 2000.
After 20 years of struggle keeping the original types latched closed on floats, I went with an STC modification which I purchased from John D. Benham at Pipe Creek, Texas. There is 10 pages of installation instruction to the door latch modification per STC# SA7400SW. Essentially it is the installation of rotary door latch assembly from C-172 F.
It has worked well and I certainly do not regret this upgrade.
I just reskined one of the doors a few months ago and serviced all the mechanisms ok. Finally got around to building a small cover at the door frame latch.
Hoping to be back flying again soon ...