A perfect angle is not as critical with the paper wheels, I have not used the newer Grizzlies, but I set the initial bevel with a file or disk sander on the old ones.
I set up my paper wheels to spin away from me at the top. Mark the wheel with a sharpie and a protracter or speed square to get a location for the angle. If the wheel was a clock, 25degrees would be about 11:00 o'clock. I hold knives and broadheads horizontal with the wheel spinning away from me. Safer and easier to hold a consistent angle. Put a big mark on top of the motor that coincides with 10:15 (25 degrees). Your grit wheel should be about 90% wax.
Be careful is right, but I have never had an issue. Only sharpen heads mounted on a shaft.
Alaska Bowhunting Supply had a tutorial last time I checked.
Best $50 I ever spent.