Quote Originally Posted by Ian Grant View Post
A far bigger problem is the 65mm f6.8 will be difficult to ficus on the ground glass, and you may need to make a focus scale. You need to find and try one before spending money.
...or stop the Heliar down to 5,6 and 1/3 (or 6,3 if the Heliar has the older aperture scale) and see how it looks.

I have a 6,8/130 Dagor on a 6,5x9 Avus, and Steinheil Orthostigmat 6,8/135 on a 9x12 Avus, and have no trouble focusing. But some people might have.