I’m still not sure what to use on my exposed ext back steps (there are 4 steps). I plan to sand them down to good wood. The tread will be gray and the risers white. They were painted with alkyd 14 yrs ago which lasted 9 yrs. Then 2 treads replaced, others sanded, primed with alkyd 2 finish coats of B M exterior acrylic. That didn’t last 4 yrs. The tread doesn’t drain well and I plan to fix that with sanding but what to paint them with for max longevity? Help!