“I’m going to be riding 95 miles of technical terrain on a hardtail and much of this time I will be seated“
Really? IME, techical-plus-hardtail means not being seated much. YMMV, natch.
Still, saddles are all about the shape of your back end, not about the distance you’re riding. If it works well then it’ll work over any distance – your bum doesn’t change shape on longer rides.
Why not throw caution to the wind and ditch the baggies? Lycra shorts do work a lot better in the saddle area – there’s less fabric getting in the way of the moving bits for no purpose other than to make you look less gimpy in the pub. Personally I don’t find bibs help in any way, but again we’re all different shapes so YMMV.