RE: Bohning jig
The Bohning Blazer jig uses a 2 or 3 degree offset tbatis supposed to be the best position.
I have a Bitz and have used different offset with the straight jig with good results.
The Bitz is easy to set-up and gives you options to adjust the offset to decide what flies best for you. Sure it costs more than the others but it will last forever. The jojan would be the next best option.