You are right, the 10 round cylinder does not have enough space between chambers to be reamed to 22 mag and than have the rims fit next to each other with random cartridges out of the box. I made a mistake on my op back in '15. Sorry to have mislead you. The 6 round cylinder is the only one that lends itself to be rechambered.

I recently posted about doing some research on the diameters of various manufacturer's 22 Mag. I found that about 20 to 25% of Federal 22 Mag is small enough to allow a ten shot rechamber job to 22 Mag. to work. But, That would involve purchase of a lot of Federal 22 Mags and then measuring and separating out the smaller ones. I wasn't willing to do that so, junked the research. I also then figured out that one could rechamber every other chamber to 22 Mag and have a handgun that shot 22 Mag, 22 LR, etc. for the ten rounds.

I found that CCI 22 Mags had the largest rim diameter of five manufacturers.