Well I deviated from my own plan. Went to Ace, Home Despot and finally West Marine and could not find the Boat Life Life Caulk or any "polysulfide" based product. Finally settled on the 3M 4000UV product, because the 3M application matrix card (showing the 5200, 4200, the "quick cure" versions, and the 4000UV) indicated that the 4000UV is especially well suited to seating metal deck hardware. 3M rates the adhesive "permanency" of these products on a simple scale of high, medium, and low. 5200 and 4200 which are polyurethane are rated high. The 4000UV is rated medium, and it is what 3M calls a "polyether" whatever that is. Definitely not silicone. I decided to give it a go. It is also paintable, but I didn't much care. I wanted clear but it only comes in white. that should be fine for my needs as my deck is an off-white and I will trim around the step with care. In my home port area Sacramento where there are plenty of sunny spring, summer and fall days (and hot summers), I figured the resistance to UV rays can't be a bad thing either. We shall see over time how it works out. Thanks again to all who chimed in. Neil