Narf,
To answer a few of your specific questions:

Use polyester thread, not cotton. It won't rot.

I prefer webbing instead of grommets. Grommets seem to want to tear out for me. The webbing can be easily reinforced.

I use a straight stitch and a fairly tight stitch length. Sewing this stuff is takes patience as it is slicker than you know what. When doing flat-felled seams, I use lots of pins (quilter pins with the big heads) and go slow. If I'm doing a rolled hem though, I can generally free hand it and keep it relatively straight.

I've made two cat-cut tarps and a Ray-way quilt and stuff sack so I'm still 'practicing'.

Tango