I am experiencing the same as Tricia. I had a good shed with 4 shafts on my first project. I went up to 8 on my second. I have 2 treadle for plain weave, and they seem to make a clean shed. Then I have 8 treadle to weave a twill, and the shed is all over the place on those 8 treadle.
I have a countermarch loom from Bear Creek looms in Ada, Michigan. Bought it used, have not found any manuals for it.
I have been watching videos trying to understand the Vastuga tie up. Is there one video which shows the tie up dimensions, and then how to fix shed issues? Is there a pdf with measurements and diagrams?