I was wrong about Polaroid Backs.
Until days before, I thought that Byron can't take any Polaroid backs, for instant film, there is only Fuji PA-45 back that Byron can hold. But now I found that for 4x5 instant film, Polaroid 550 holder is exactly the same as Fuji PA-45, so I should add Polaroid 550 into the list. And for 3x4 instant film, that Fuji PA-145, Polaroid 405, Polaroid CB-103, CB-101 for 4x5 format camera. They need to be modified, if you want them on Byron.
This is Polaroid CB-101, all we need to do is to cut the extruding part for hook
And for Polaroid 103 back, similar modification
After lathed by my mechanist, now the back is feasible onto Byron
But some problems to take care of, first, the film back lock, second, dark slide can not be used, meaning you have to shoot all 10 films before changing other back.
"It seems 3x4 instant film is back on the menu, boys!"
--movie "Lord of the Rings- Two Towers"