u/Freedom-Of-Trades

I got a Montana Radial base tune with a 3 degree side bevel. I'm going to buy an edge guide to tune the sides, but I have a novice question.

Normally, you determine the side bevel with a flat base, (a 90 degree with a 3 degree side bevel is 87 correct?)

So since the Montana Radial base is multiple different base bevels, do I still buy a 3 degree bevel guide for the sides, or is the a formula that comes into play because it's not a 90 degree angle? I would guesd just get a 3 degree but I want to be sure. Thx.