My sitbones measure 130mm c-to-c, a bit wider than yours, but I do fine on a Terry Butterfly (155 mm width). I rode that saddle for 9 days straight, averaging 62 miles daily, on a loaded tour, without any issues. I just ordered a Selle Italia Lady Gel Flo (160 mm) to replace a saddle I really liked the cutout on but which ended up being too narrow at 140 mm (I hadn't measured my sitbones when I got it) and caused/aggravated a bad saddle sore. Just a small increase in width can make a huge difference in where your "bones" are supported.

From the sounds of it, I'd think you'd be fine on a 155-160mm saddle with a cutout. Your choices get a lot more limited if you go wider than that, and you may not need the extra width. It's worth trying this range first, I think. Some places will give you a refund if you're not happy -- Terry gives a 30-day comfort guarantee, I believe.

Good luck!
Emily