What level of rider is currently riding him?
If he's being ridden in lessons, I'd ask to watch a lesson.
I'd ride in the tack they provide and then if you get to the next level then you can always ask about using your own saddle but I'd have the owner/trainer (if owner is comfortable with that) check the fit with and without you in the saddle. As for bridle, if they want a specific bit used then they may let you use what he's ridden in.
If he's being ridden in lessons, I'd ask to watch a lesson.
I'd ride in the tack they provide and then if you get to the next level then you can always ask about using your own saddle but I'd have the owner/trainer (if owner is comfortable with that) check the fit with and without you in the saddle. As for bridle, if they want a specific bit used then they may let you use what he's ridden in.