I own 3 sigs. A 220 in 45 ACP, a SigPro in 9mm and a swiss surplus 226 in 9mm. Which of these would be the best host for a .22 conversion unit with a can? Where is a good place to shop for a factory sig .22 unit ? What can I expect to spend on one ? Thanks all..

220/226 take the same top, obviously, different mags.
($2-300)

They don't have a kit for the sigpro.