Hi Luci that is one gorgeous horse!
Don't put up with pain. It will stop you from riding. And if I remember you have a 50 miler planned.
My two cents on shorts- I got the Sugoi Evolution shorts recommended by my female LBS owner. They are not as expensive as the ones Nanci wears. They run around $69.00 I think, which is a lot, but they are fabulous with a great chamois. I don't wear baggies, they make me look fat. I have a pair of Pearl Izumi capris and yes, the chamois on the pearls are massive.

Be sure to go commando under the shorts. Undies will cause chafing.

My saddle has a slight cut-out. Not sure if it matters. Any saddle will cause soreness on the sit-bone area if your butt is not used to riding. Your LBS should be willing to let you try them out a few days at a time. The internet is great for discounts on stuff you know you will keep, but the LBS is still the best when you aren't sure. I have lost money on shipping that I would rather just give to my LBS. Plus you get their devotion to you when you spend money with them.