So, I didn't get a chance to go out and compare the two yet, but I sold my A7R4 and had the Laowa 9mm FF left over...and I noticed it kind of fit instead of the mount of the GFX. I know that the flange distance won't let it get focus, but if you used electronic shutter and retrofitted the mount so it fits kinda inside the shutter square I almost think it might work?
Here is a shot where it just touched the square, don't worry the sensor was unharmed.
