The P229 in 40SW is awsome. The P229 was specifically designed for 40SW and not the otehr way around like in most handguns in 40 that started their life as a 9mm platform and then got a released version in 40sw. The Sig P229 was drafted with the 40sw specific dimensions, that is why P229 in 9mm are overdesigned.
So first congratulations on your fine choice.
for range practice ammo I prefer the 180 gr. If you are thinking about reloading for 40SW, then the trick is develop a regular load for 180 gr bullet, and if you want something milder use a 165 gr bullet for the same load that you use for 180. You will get a fun soft recoil load that will feel like 9mm and most probably around a 9mm power factor. If you want loading recipes I have some recipes for titegroup, Winchester WSF and Win 231 and Bullseye. Let me know when you are ready to reload for 40SW.