As a reference point, my Infinity grips are clocked about 22 degrees.
But Mel is right, you should test-fit to determine what angle works best for you.
One way you can do that is using the co-pilot stick (i.e. right seat), since that stick is removable and can be rotated at its base. This of course is possible only assuming you're doing a mirror image installation on the stick grips, and assuming you haven't drilled the base of the co-pilot stick yet. If this is the case, then keep reading. Fit the right hand Infinity grip to the co-pilot stick. Then insert the stick into its base and rotate it until you find the most comfortable position (with your right hand, sitting in the co-pilot seat). That's your answer. Now mirror that clocking angle for the pilot stick on the left side.