I like the J and LT the best for Bart
I like the D and PW the best for Joby
When a Dealer sends all the fit forms for a Horse, I really hate that, tells me something about them, it is also so confusing, 99% of using Horse Breed and Size Specifics can be determined by 3 or less fit forms, to send more is crazy, some of those forms are for Draft Horses....
The 2nd thing is with any Saddle on a Gaited Horse it also depends on the Style of Tree, A-Fork, Wade, Trail, etc.
It matters also how the maker shapes the leather and fleece he attaches to the tree on the underside of the bars and curves the leather to attack under the pommel.
I would suggest an A-Fork Style Tree even if used for a Trail Saddle, those Trees allow for the extra high withers your Horse has. For a heavy duty roping saddle or similar I would suggest a Wade style as the inherently have more wither clearance than roper trees.
Of course the Maker who sent you the Trees is ultimately responsible for the fit, but those are my estimates of which fit forms are best.
I would also have the saddle maker send a couple of Bare Trees for final fitting, it is much cheaper to gamble 30-40.00 on a tree shipment to be sure the saddles will fit.