I made a TT1 and have somewhat limited sewing skills. There are some tricky measurements and fine tuning, so if you aren't comfortable working with large runs of silnylon, I would go ahead and buy the sqall instead of ending up with a $60 mess. The squall is also quite a bit bigger in terms of livable space, so that should also be a consideration. The TT1 is an excellent tent, but you have to be pretty close to share it. The TT1 has excellent plans, though I found making the perfect beak tricky. Mine keeps out the weather, but it takes awhile to get a pitch that keeps it taut. Paired with a tyvek ground sheet, this is the tent I use most during the summer.
I should also mention that if you use the source for tent poles in Vancouver WA, make sure you buy the right grommets for the tips. I have heard of several people who did not consider this and had to either sand the tips of the poles down, or had to resew the whole grommet nylon tab.