Just been reading thru this thread a bit and was wondering if anyone has tried a 2 part silicone as aposed to the stuff out of a caulk tube. I used to use the stuf to make prosthetics and it was quite easy to work with. Not sure if it would make a difference just that because its 2 part curing not air curing you have more control overe it. Also the 2part stuff may impregnate the material better and therfore provide better water protection.
I haven't read all 44 pages so if iv missed something sorry for wasting your time.