I'm currently using a 3 cord 100% flax linen thread. I'm mainly making belts and wallets and I like the stitching to be a feature (while my work is still looking "home-made" anyway =] )
Yea I've been meaning to look into yet more threads and your mentioning of a 1000% betterment is exciting haha and YEA I've run the lighter along my belt stitching. Seems to be doing the trick. I'm yet to try it on the wallets. Wallets, being in, and being taken in and out of pockets would in my opinion put items as heavy use in regards to the stitching anyway (the friction n stuff).
I've been using a lot of black thread recently (that is plain thread that I dye myself and then wax in the way that Jimmy Eng does) so I'm thinking that I might just buy a spool of black prewaxed thread to help solve my problems. I assume that a mass produced dyed and waxed thread might give more consistent and pleasing results.
Thanks for your reply, I appreciate your time =]