Saddle fit: will an A frame horse stay A frame?

[fivestrideline]

This is both a general question and a specific one. If a horse traces/measures as an A frame build, how likely are they to stay that way? Or maybe, how likely are they to grow into a more U or open headed tree shape? I understand width and muscling can change some aspects, but I’m wondering about basic shapes.

Specifically, I have a coming 5 year old OTTB who is letting down from the track and still very much a work in progress. His tracings are pretty “normal”, with the fitter saying he’s built perfectly for a Wintec. I’m a leather snob so that’s a no go, but I am curious if I may be shopping for a A frame saddle now and something entirely different down the road.

For fun, here are his tracings from today (somewhat distorted due to laying in my tack trunk for the pic)

And him when he first arrived:

[sheltona01]

He will most likely stay fairly that shape. His back looks nicely muscled and his posture is good. I will try to post more thoughts later.

[GreyDes]

My horses that have needed a hoop tree have generally started with a no withers U shaped back. I have had to change saddles/tree width on A frame horses as they’ve matured, but haven’t had to move between tree types.

[fivestrideline]

This is what I’m wondering about! Thanks!

I expect to need to adjust width and that sort of thing, but I’m wondering how common it is to need to “reinvent the wheel” as it were.

[candyappy]

My experience matches @GreyDes 's. The width may change a bit with age or weight/ fitness changes but the tree shape stays the same.