I was hoping to compensate for the difference between the film guide removal and where the instant film would sit, but using a focusing glass placed where the instant film sits and check/adjust the camera's focus setting... but like you, I don't know just yet how this is done or if it can be done... I have read that infinity is an easy fix, just change the extension point of the lens a little farther out. But the linkage that moves the focusing from lens movement into the viewfinder may be the only way to adjust focusing to match what I see on the film plane glass. Either by shortening or lengthening it, or there may be an adjustment screw? This is something I also would like some feedback on before proceeding with the conversion.