This is the sprang I started last month (see here) and finished a couple of weeks ago. I made it on the experimental frame as continuous warp. Then I sewed up the sides and cut the strings to open the top. I was trying to tie off the ends when the thing started unlinking. Highly annoying. I was really mad at it for a while. But I came to appreciate the good parts. It proved I can sprang on cardboard frames. I can do pattern changes. And I also have a different idea for the design. More to come in the future.
Have a good day!
EDITED TO ADD: Musing on an adjustable sprang frame. Someone suggested using long screws for sides of a frame. That might be workable. I think two 12 inch long pieces of all thread screw rod, two wooden dowels drilled to accept the screws, and eight hex nuts to adjust the position of the dowels.
Or two wooden dowels drilled to accept two other dowel and maybe another screw to hold it in place?
All of which is more work than using more cardboard but being adjustable could make the difference.