Hi Mohammad,
Coming back to your 5 questions, here are my 5 cents:
1. Good
2. The 340 works well on my Simpson Davits. I lift it with my 15HP Yamaha on.
3. I had the 340 on the  sundeck without releasing the air, but it only fits  angular
4. Offshore my 340 is not at the Davits. Why should I turn an extremely seaworthy boat into something risky?
5. Hypalon. Chaps in both cases!

Hope that helps.,
Alex