Re-stitching by hand ?!? <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" /> (shivers) Not something I would recommend unless you like tedious repetitive work. If you can get your hand on any sewing machine, that would be faster, even if you had to crank it by hand.
Get some v69 thread from
www.Sailrite.com, and a packet of size 20 needles. Most domestic machines will do a fair re-stitching job if you just help it get going, unless the tramp is made of super-heavy materials.
Sailmakers will do this for you fast and with the proper thread. That is the easy way to do it, just negotiate a reasonable price-frame before you let them loose.
How will dental floss hold up over time, especially under UV radiation <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />