I'm a Sig-lover and use a p220 "Carry" model as a primary concealed-carry weapon. Of course this shortened version is still not what anyone would call a light or slender gun. So I did some online research to find a set of grips that would narrow the profile, yet still look good and feel right to me. When I couldn't find a reliable side-by-side comparison on the forums, I bit the bullet (or the credit card) and bought a few different brands/types to make my own comparison. I can't provide input on everything available. Some were just not of interest to me. But I thought I'd post what little I have learned in case it is helpful to someone. Note: I have not tried a set of Nils grips yet, but understand that they may be thinner than the factory wood grips...and of course they are beautiful and expensive. I also did not buy the Hogue or Pachmayr rubber grips for this experiment. I use the former on other guns, but did not want them on my fancy-schmancy 220 Carry models (an Equinox and an Elite).
In order, from thickest down to thinnest:
Hogue wood grips (checkered) beautiful, but may be the thickest grips made for that gun
Sig Elite model wood grips
Sig Equinox model wood grips (they're a slightly different design, but essentially the same thickness as the Sig Elite/standard wood grips)
Sig "thin grips" (these are not their standard rubber grips)
Hogue aluminum grips (the thinnest I know of) but the checkering is very sharp and is not comfortable to wear IWB without a T-shirt).
The Hogue "extreme" aluminum grips, while a little rough on my love handles, are very comfortable to my hand, and make for a very secure grip on the gun. Nevertheless, I may try a set of the un-checkered version on another 220.