You didn't say what you are using for the edge finder, but it is obviously not the renishaw probe system.
I have used a basic .200" tip diameter edge finder for years. When using it I have a simple procedure for setting edges that I use and teach to others, little no math required.
When touch off an edge, X or Y, I just move the tip to the edge in the .001" setting jog and when I touch the edge I just switch to the Z axis jog to move up and when I move it up to clear the part I stop on the "O" (zero) point on the jog handle. Then you just go back to the axis you are setting and turn one full revolution more. That will be .100", or the center of the .200" diameter tip. That means that this is your setting for that axis.
It becomes easier as you do it more. You get to the point where you can almost stop at Z zero without even looking. Just crank the tip up until clear and stop with the little knob on the jog handle at the bottom and verify it is at zero. Move over the .100" and set that axis.
After setting that axis you don't need to hit jog again, just leave it on the offset page. You just hit the X, Y, or Z again and continue to set the next edge, as you will still be in jog mode even though you are on the offset page.
I can do a simple X Y edge find in about 20 to 30 seconds.
Holes are different, but you can reduce the complexity of the math easily. When you probe a hole, just move the tip into the hole at approximately the center. Start by setting the Y axis, as the human eye will locate the center of X better than Y, so start there.
Next touch the tip on the front or back side. Go to the position screen and go to the operator page. When in position just hit origin and the reading will be set to zero. Move the tip to the other edge and the readout will have the diameter of the hole minus .200 tip diameter. For example, if you are probing a 1" diameter hole, the readout will be .800". Whatever the number is, just divide by two and move the tip to the center or .400" in this case.
You do the X axis next and you are set to go to the offset page and enter both X & Y at once.
It takes only about 30 seconds and instead of say taking X-16.6763 and subtracting X-15.6763 then dividing by two and then adding that number to the smaller of the two and entering that number by hand, you just have to divide the difference of the reading, ie .800'' by two and move to that position and you are in the center.
You can do both X and Y very quickly, about 30 seconds depending on the size of the hole.
Still requires some math, but much easier math and usually simple enough to do easily in your head.
It is much more difficult to explain than to do, believe me.
Mike
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28