Jay - You can get artificial sinew at www.jastown.com look under yard goods , might as well get the big spool.

I've only used 8 oz nylon from George Dyson and think it is a good choice for a lightweight boat, there is heavier nylon available for more abrasion resistance. As to aircraft weight dacron 2.7oz - 3.7oz I've never used it and though it seems very lightweight people that I've talked to say it is a good choice( it is the cheapest skin and the easiest to apply). If I did use the light dacron I would peg 1/4" thick UHMW plastic (the white splippery stuff) to the keelson and the bottom chine on either side of the keelson.

In general skin boats are much stronger than people think, their impact resistance is quite high.If they have a weakness it is in abrasion resistance as in dragging over rocks (some people think this is okay!) but being light in weight under 25- 35lbs they are easy to carry.

Tom