I use a cheap electronic touch probe in Mach 3 using the blue screen set for touch probes. I have a jack in the front panel of my cabinet to plug in the touch probe when I want to use it, and set it aside when I don't need it.
My touch probe is neither concentric or straight. I do a find center, zero X & Y, roate the probe 180 degrees and repeat. Then I split the difference. Center. Takes a lot less than five minutes. If I rushed I suppose I could do it in under one for a smallish hole. Usually I take my time and it takes 2 or 3 minutes.
Its pretty darn fast.
I could do it with an indicator, but I already had the probe for scanning parts so why not use it. I use it on both my Taig and on my MaxNC. I don't use it on my chinese router because I do not have enough clearance for most parts with it. Heck, I may use it on the Hurco when I finish converting it.
CamBam will allow you to do your five holes really easy. It does all the math for you. I am sure other CAM software will too. In CB I would draw a circle of the desired radius with a center at 0,0. Then select the circle and click Draw>Point List>Divide Geometry, then enter 5. Boom. You have 5 points mapped exactly the same distance apart at excatly the same distance from the center. You can use them to center circles for pocket MOPs or you can just use them for peck drill or spiral milling drill mops. It took me longer to type this than it did to double check it in CB to make sure I gave you good info. Also, if you want to try CB the current release is fully functional for 40 executions.
Bob La Londe
http://www.YumaBassMan.com