The other thing to bear in mind is that the stresses on the sail are so light, that if your stitching does start to go, it doesn't instantly unzip like it would on a Bm mainsail.  The seam can easily be re-stitched by hand, using a domestic needle through the old needle holes, on the next calm day or when you get to harbour.  If you used double-sided tape as a temporary measure while you were sewing, the sail will hold up for a surprising length of time with that alone.  As long as it's not acrylic, which doesn't like double-sided tape.

I use only black polyester V69 bonded thread. After 6 years with the current sails, including plenty of time in the tropics, I am seeing no degradation of the thread. Black lasts a lot longer than white, and you can see broken and chafed stitching readily against most colours. 

I've been doing research into using PTFE thread to sew our sails, after seeing how quickly UV rots the thread in things like biminis. PTFE is considered "lifetime" thread and is expected to outlast the fabric. The downside is, it costs a LOT more than polyester thread.

I have seen three brands of the stuff:

Tenara - $US 129/8 oz
http://www.sailrite.com/Tenara-Thread-Canvas-Awning-Camper-Tarp-Outdoor-UV-Resistant-Thread
8 oz = 1595 yds

Solarfix - $US 165/16 oz
http://www.miamicorp.com/default.aspx?page=category%20search%20results&CatUid=29884&CatList=34912&Parent=29874
8 oz = 1125 yds

Helios P - $US 99/8 oz
http://www.rochfordsupply.com/shop/Thread_and_Bobbins/Polyester_Thread/Helios_P_-_Lifetime_Guarantee_Thread/index.html
8 oz = 1700 yds

Solar ThreadT and Profilen are alternative brands of PTFE thread. I haven't found sources for them yet.

This research brings up the following questions:

• How much thread did you need to sew your sails?
• Has anyone used PTFE threads with success?

Thanks for any thoughts on this. I'm leaning towards the Helios, in part because I plan to order our Odyssey III from Rochford anyway.

~ Meps