I also suggest adding a seat saver. The Heather Moffett one is called a Hip Saver I think. You can make your own from a Cashel seat saver. The idea is to add a firm foam layer on top of the saddle seat that will lift you a little higher. The foam needs to be cut so it is slightly more narrow than the too wide seat of the saddle. this creates a better twist.
I ride a Bob Marshall Sport Saddle. On a wide horse the flat seat of the BMSS can put a lot of pressure on your hips. I thought this out and realized that the thick, firmer foam of the Cashel pads was just what I needed to get lift. I actually trimmed the foam pad so it was still wide under my seat bones then tapered to a narrow width under my thighs and pubic bones. The shape is kinda like a wide comfy bicycle seat.
Get one of the western cashel seat savers, not the style that goes up over the cantle (unless you need to make the seat size smaller). You want the style that just covers the flat area of the saddle seat. Open a seam of the fabric cover just enough to pull the foam out. Trim the foam with good scissors, moderately at first. Test the fit and trim away more if you need it. Once you have it right you can hand stitch the seam closed.
Another suggestion; if you can lesson any bulk under your legs then your leg will hang closer to your horse. I found it helped to get rid of the western rigging and cinch. I put western-to-english converters on my saddles so I can use a dressage girth on my endurance saddles. This helped a lot!
http://hillviewfarms.com/girths.htm scroll to bottom of the page to find the converters that I buy. Very good quality leather and quite cheap.
Bonnie