My tarp took days of nothing but sewing (luckily, I'm a teacher, so some time off in the summer is not out of reach). I'd second the not hurrying part. There were several times that I made a serious error, stopped, backtracked, and started over. Yes it added many, many hours to the project, and yes, I had to take the TarpTent out when I would have preferred the tarp, but it was worth it in the long run.
Now I'm done, and I have something that I'm really proud of. It's not MLD quality sewing, but it should hold up in any conditions I would need to deal with.
Anyway, I'm excited to see what else you contribute to the MYOG side of BPL. In my opinion, it's the best thing the site has going for it.