What magazine to use for german 229

Question, and apologies if already answered. I have an older sig p229 that I'm planning on converting from 357sig to 9mm by having a barsto barrel fitted. I understand that it recommends 9mm magazines, but I don't know if it needs the older ones with the more narrow mouth, or the newer -1 e2 ones that have the wider ones. I know the older p229s 9mm require the narrow mouth due to frame size, but as it's converted from 357sig (which have a wider frame), I'd assume the newer one is a better fit.

Thanks