OK sorry I was not clear did not mean that they were chemically interchangeable meant that a prior reference in this thread was to using Sikaflex to install windows in Vans world and Silproof is what is used in glassair world. One is polyurethane the other a hybrid silicone. My bad. Sikaflex by the way was also used to seal the seams during assembly of my floats. I used Silproof when I installed the windows in my Sportsman.Caution, Silproof is not GEs version of Sikaflex. I would hesitate to using any silicone sealant where it will be exposed to view. Look at any older application such as a motorhome, and you will find silicone seaslant loosing it's adherence and collecting dirt. Once silicone has been applied almost nothing adheres to that same surface and that includes paint or polyurethane.
On the otherhand polyurethane is rather permanent. For marine applications it is stated on the tube that it should not be used where removal or replacement is planned. I have seen it pull off jellcoat when changing a stanchion.
As for not being able to paint and falling out Silproof has been used to bond windows on 100’s if not thousands of airplane windows. Painting concerns are addressed in how windows are masked. Removal and replacement is easily done. Experience with Silproof at Glastar/Sportsman goes back ~16 years
But hey do whatever pleases you and you have best luck with. Was just sharing what I did.
All the best