You don't need new shafts Ed, just machine
flat spots where your set screws grip. Drilling a hole for a set screw pin might weaken the shafts to twist off/break at the holes.
Here's pic showing the hole I had to cut in the 850 body b/c the vertical mount motor being too tall.
I'll get you some more pics tomorrow or Sunday for you to tilt your head & wonder Elliot.