I'd go with 231 before HS-6. I started using 231 but I switched to TG for better consistancy and I was able to get a better bulk deal on it. HS-6 is a slower burning powder which is needed to get the most out of a ported pistol.
If you are using a 180gn bullet I would suggest 4 grains of 231 at an overall length of 1.2" if you are using a 1911 that has been free bored to accept a longer round. If you are not free bored or are using a smaller framed gun then I would suggest 1.135" starting at 3 grains and working up, with a 180grn bullet. When I used 231 I was putting in 5.5 gr under a 180gr bullet loaded to 1.2" and averaged around 970 fps out of a 5 inch 1911. If you ask the guys over in the action shooting forum about a good ".40 minor" load for your gun/bullet/powder setup you'll get some nice light loads.