Have you looked at MiterSet? It's a gauge for setting your existing miter gauge dead-on accurately. Built like Aerospace hardware and allows settings to 1/2 degree increments. Using these only requires placing pins into the desired holes for the angle desired, and then placing your miter gauge against the pins and locking it in place. Then placing it on your table saw.
A second version of the gauge allows setting your miter gauge for the angles needed to make segmented circles. You just select how many segments and it does the rest. Some of these angles need to be accurate out to 3 decimal places for a perfect fit. This gauge does it without the calculations.
I use my OEM Delta miter gauge and set it up with the MiterSet for my needed angle cuts. The only requirement is that your miter gauge needs an 3/4 X 3/8 bar that fits your table saw miter slot accurately.
MiterSet Package Set For Table Saws You can buy just one or the package of both.
Charley