That's how I mounted mine too. I ended up welding a ~1.5" threaded spacer to the outboard side of the clutch pedal arm
I have the pushrod mounted to that so it's a straight shot into the master. It would be nicer if the firewall was flat there, I'm gonna fab up some spacer someday to even out that area. Definitely not easy to package. The under dash setup would be easier, if there was a good way to mount the actual pedal. I tried the angle mount to use the factory linkage hole, but my headers were in the way.