I wanted to do this a couple of years ago. Counting the number of turns required to advance to the next frame doesn't work, for a couple of reasons. One, as you near the end of the roll, one turn pulls more film along than at the beginning of the roll. Two, 220 is marginally thinner than 120, and the lack of backing paper for much of the roll compounds this. In the end, it just wasn't worth it and I moved on to some other trivial problem.

If one were really dedicated to finding out, one could sacrifice a roll of 220 by loading it in the camera and leaving the back open. Then wind to the first frame, mark the extents of the frame on the film with a Sharpie, wind to the next frame (counting as you go), mark that frame, and so on. Take notes, compile a chart, realize that by the time you've done all this you could have shot two rolls of 120 with much less fuss...

Hmm... Sounds like a project for a dark and rainy weekend.