Tapping heads.

I have an 1100 and want to do threading, both external and internal.
1. Internal - Tormach lists at least 3 (sure there are plenty of other brands), but not clear how to choose? I won't be using it that much and don't want to spend a fortune (mostly small taps in aluminum 1/4-20 and smaller) ... Recommendations?

2. Most common way to do external? (again, small sizes)...


Thanks!