I have a Technika III, 1956, with the International back. My focus appears to be off with focus falling a little beyond the focus point of the ground glass. While I try and find the right tool to make some measurements I'm wondering if the back on this camera typically incorporated shims between the GG and the frame? My camera has none. Or is there some other form of adjustment such as the screws above and below the tension spring holding the glass in place?

If I'm missing shims, are there any good suggestions where I might find some or perhaps an alternative method of shimming?

Thanks,

Dennis