: Your post gives me an idea - I may try panty hose as a no-seam option,

The panty hose may be all right for you, but that 1/4 sacle boat model may be a bit too long for a good fit. 16 foot boat calls for panty hose that fit 4-foot-long legs!

: if I
: can find something with a tight weave, like tights (that might look a
: little weird in the store, me checking panty hose fabric textures). I
: suppose it ought to shrink - worth a try, anyway.

Ask a female friend or relative for a used pair and you'll save some money. Either that or shop at a "dollar" store. The knit on hosiery allows them to stretch (a lot), and gives them a rather gentle shrinking ability. While they may pull in tight on your models, they will be ready to stretch out again under any kind of gentle pressure. You may be able to counteract this by spraying them with a coat of paint. Hopefully the aerosol application will put on a light coating which will dry fast and won't cause the material to stretch out. When it dries, hopefully the paint film will trap the fibers of the hosiery enough so that the kayak skin stays taut.
a few light coats of paint will also help amke he material waterproof. As a stretched-out knit fabric, it would otherwise be very porous.

PGJ