I have never used Nylon, but the wisdom of the web says that dacron is a little less tough, but easier to coat using onepart polyurethane or two part urethane or oil based paint. The skin can also be heat shrunk to get a very tight fit to the frame. Nylon is supposed to be the toughest covering available, but cannot be heat shrunk, I saw something on this forum about a person who soaked the skin with water to get it to stretch, then skinned the boat, when it dried out the skin shrunk again and became tight. Apparently the nylon requires a two part polyurethane (expensive) or halpalon (expensive) - another two part coating which has somewhat toxic chemicals in its construction but is extremely tough. A lot of the inflatable boats and rafts are made with halpalon: I have not used halpalon or the recommended 2 part polyurethane. However automotive clearcoat is a 2 part polyurethane which I have some of and I might try next time.

Do you know of a reason you need exactly 9.8oz nylon? Everything I have read has suggestion ranging over the total available material, with no real justification for any particular weight. Except, heavier is tougher, and lighter is lighter and tough enough. I have no experience. perhaps someone else will chime in.

The ballistic nylon is 9.8 oz. I was told 8 oz nylon would be ideal
: but it looks like George Dyson is out of that (I did email him,
: just in case).

: What are the advantages/disadvantages of Dacron v. Nylon?