"she misses the focus on her seat that the other barn provided"
I've been making the switch over from English/Australian saddles to a western saddle since Thanksgiving. Something that is increasingly obvious is that a western saddle tree allows more options in what is "correct" in a seat. The saddle tree extends further back and covers a much larger area, so the PSI of any rider action is reduced. The bad news is less feel of the horse by the rider. The good news is less feel of the rider by the horse.
Want to ride with your feet forward and your spine straight? Do that with Mia in an Aussie saddle, and she'll slow her trot to a light jog to save her back. Do that in a western saddle...and she did a fast trot for a mile home, then cantered around the arena.
The saddle my daughter uses locks your thigh at a particular angle. I dislike it. My daughter loves it. But she stays balanced on Trooper, and Trooper is happy, and the horse stays between her and the ground even when the cinch strap comes undone while cantering down a trail...so how 'wrong' is it?
I asked a question about western riding in this thread: Weight in stirrups western riding - yes or no?
The answer was largely...it depends. If you look at western riders cutting cattle, roping, barrel racing, trail riding, performing western pleasure, etc, there are a LOT of valid 'seats'. Weight in stirrup or barely touching. Heels down or foot level. Heel under hip or heel out front. Contact with lower leg (impossible in some western saddles and a bit funky in any western saddle I've tried) or no contact with lower leg except for a cue.
When I was taking lessons, I asked my fellow students what the cues were to ask a horse to canter. I had read several books on dressage, and expected an answer about put this leg here, that leg there, make a circular motion with your inside hipbone, adjust the outside rein like so, etc...and instead, after everyone looked puzzled for a moment, one lady replied, "Kick harder?"
If a person want to do something specific - roping, or barrel racing - then western riders, like English, can discuss at length just how to get the job done or why they like to do X instead of Y, or y instead of z. If you go to the barrel racing sub-forum, for example, you can find detailed discussions about 18 different bits for different horses. But for general purpose riding, it seems to boil down to: Is he doing what you want? Are you happy? Is your horse happy? If you have 3 yeses...then enjoy!
My daughter and her horse, on one of the few shots where her feet were briefly in the stirrups...and with the cinch still attached (