Too many variables. Stay with a non flex. Your saddle may not be the problem but she knows what saddling means - work. I'll bet she's real tired when she gets home after an 8 hr ride. Are you feeding her during this time, either by dismounting and allowing her to graze or taking hay and grain along for her?
My saddle is to narrow for her so I have been borrowing saddles and would really like to just get her, her own and not have to borrow or worry about my saddle hurting her. Btw I have not ridden her in my saddle for very long because of the fit problem. My trainer let's me use hers and so does the BO so I only ride her in a saddle that fits.
She is very lazy! Lol which is why I'm hoping she'll come around. She already has done a 180 on saddling but you can tell she hates it. Before she would literally run from the sight of a saddle, shaking and quivering. Now she stands still but fidgets a lot and is not the happiest. She was also beat by a previous owner when she wouldn't stand still while saddling. It started as fear thing and now that we worked past the scary monster I think it will just take time, exposure and getting her use to consistent work.
I normally don't take her out on the 8hr rides because I need a saddle to fit her and my 'borrowed' one is usually being used on another horse who is with us on the ride. She has been out twice on the long rides and it was lots of walking with lots and lots of breaks for them to graze and drink. She does amazingly well on these rides but yes she is generally pretty tired afterwards. I want to be able to take her out anytime and not worry about the saddle issues. Posted via Mobile Device