You will like having a harness set up for each horse, so you don't have to bother changing the straps.
I have the Ozark also. That company will certainly work with you well. Lots of topics on here about kinds of harness; you might want to search the forum.
If I buy another, which doesn't seem likely, I might look around a little more.
My old harness came from Big Dee. I see they are no longer making miniature harness, but it has the nicest bridle I've ever seen. The fit is great, the blinders adjust perfectly. I've been using it for 10 years and it still looks great.