Ref the waterproofing...
I've used Fabsil, it was nasty stuff and to be honest I was never impressed with the level of waterproofing.
I've used Nikiwax waterproofer for years, I stick my bike gear in on a cold wash, then put it through another rinse cycle and pour in 100ml of Nikiwax in the draw and wash it down with an extra litre of water.
Water/rain just beads up on the outside for quite a while after even when riding everyday.
That reminds me, it's bee a while since I washed and re-proofed my gear.
The problems with material degradation and being prone to tearing is due to UV damage... keep it out of the sun, but that's kind of dificult if the bike lives outside.
I had a cover over my bike when it was parked against the house on the south facing side... the side facing the wall was dark black, the side facing the sun was pale grey and crispy after about a year.