2)I have not heard of rain causing any problems.
3)Your weight should be no problem.
The 1" webbing. Ask them to sew the loops on for you at a small charge.
I used to use Speer webbing but have recently switched to polyester webbing.
2000lb. strength and less stretch than the Speer webbing. You would have to sew your own loops or get someone to sew them for you. www.owfinc.com/Hardware/Shardware/webbing.asp
It is the woodland green polyester webbing.
These are the lightest full strength carabiners on the market. 1 oz. each.
There appears to be a few others new to the game that are similar in weight.