Her back isn't obviously sore, but I've never gotten her backed checked by a chiro or a professional saddle fitter. I have a specialized that I shimmed myself. Since getting the new saddle, however, she top line has improved. So in the very least she's less sore than last saddle.
I could actually use some Body Glide for myself! I think I've actually seen that stuff at Walmart. Sounds like a easy thing to try next ride.
I do ride with a somewhat loose girth. I can fit all my fingers under it without much resistance. My saddle moves back and forth probably four inches, judging the range of sweat marks.
Southern horses don't grow any hair until December usually.
My horse sometimes skips the hair thing all together and just insists on staying slick.