I found some notes from "Back in the day" on when I ran the YS 61. On a 12x12 I had the set up 16 inches from the glow plug to the first baffle on the pipe. This sounds right.... I remember it being a L-o-n-g set up..... but I would still shoot for the mentioned RPM range as above with what ever the pipe length you use is. It may differ for you since I was in MN at the time and you are in AL.