...and if you switch horses in 5 years that might mean a different saddle anyway. Sounds like it's best to get a saddle that will fit your needs for your current horse and needs without breaking the bank knowing you will most likely need a different one once she retires. If it helps at all, I have a freakishly long lower leg that shoots over the flap of every forward flap jumping saddle I've ever sat in. For some reason, that doesn't happen in the T8 AP. Also, it does offer a nice deep seat and good balance for dressage. On the other hand, if you hate deep seats for jumping, Thorowgood isn't the one for you. I like the security of it, but I know the cantle can get in your way if you're doing novice or training and need to get into the back seat to do down banks and drops.
You just have to see your distance...you don't have to like it.