If the coating isn't particularly abrasion resistant, then I do think fabric weight is important! ;-)

Doing my own abrasion testing with cheap polyurethane (Pro Finisher brand, $20/gal) coated 8 oz polyester (Dyson), it held up well except for very small areas where the coating was completely worn away (mainly along the keel and first chine) but that was about 5 river miles worth of bottoming out every few minutes. Maybe our rocks are smoother? ;-)

Ultimately, it seems like skin boat fabrics won't hold up well to abrasion on their own. Once the coating is worn through the fabric doesn't stand a chance.

The coating I'm going to use is a water-based polyurea: http://www.fox-ind.com/datasheet.asp?sheet=233 Its nowhere near as expensive as DuraTuff...

I have two boats coated with Zar and they seem to hold up well. The one that is 'satin' scratches and scuffs much more easily than the one that is gloss, FWIW.

: After my little ride Saturday I have to say skin weight is
: important! The more I look the more I find wrong with my boat.
: That little ride just beat the heck out of the skin. It's ruined
: in 15 seconds! But I also agree that the coating is very
: important, no doubt. What coating are your talking about?
: DuraTuff? I have thought about trying it too. But ZAR is about
: half price so I just ordered a couple of gallons of it for my
: boats.

: Anyone tried a Neoprene/Hypalon coating? That sounds like it might
: be a good choice too.