Congratulations on your new saddle journey.
My big piece of advice, is to vet your fitters carefully. Ask in your local social media groups about experiences. Do your own research on their certifications. Make sure they are certified independent fitters, versus “fitters” (often called representatives) for a specific company. Many representatives will advertise themselves as " certified saddle fitters" ex. “Certified Stubben Saddle Fitter” – what they really mean is they took a 2 week course by their specific brand, to learn about their product. Anyone can take and pass this course. This title is understandably confusing and misleading - they are no more “certified fitters” than I am a “certified chemist”.
First thing I would do, is get wither tracings and consult with your fitter if you trust them. Certain brands will have specs that won’t work with your horse. To give you an example - I love Amerigos – but their panel shape has never worked with any of my horses (TBs) who tend to need a flatter, broader panel than what Amerigo seems to supply.
I am happy with my custom Black Country, but how I acquired this saddle is a pretty unhappy story. Like you, I finally saved up enough to get a custom saddle after years of saving. I did my homework. I talked to local people. I went with Stubben since their Zaria line was apparently great with TBs; I used one of their reps (who, btw, also used the misleading term “saddle fitter” when she was just a rep). The rep told me my then-saddle wasn’t right, and told me I needed to go custom. I bought a custom saddle to their exact specifications and my horse went from willing to unrideable. Involved the vet, my chiro, even my trainer - every professional in my circle said this saddle did not fit my horse – except the fitter, who then blamed my issues on my girth, and then my riding. All of that to say, I listened to the horse and scrapped the saddle. I ended up riding the horse in the old BC I had lying around for a different horse - and 2 years later, had saved up enough to go custom. I ordered the exact copy of the BC saddle I have - on paper, this saddle isn’t “the perfect fit” for my horse - but he goes very happily in it.
Make sure whatever you ride in, you can get more than a month’s trial. I’m finding out more and more, that 1 week, 2 weeks, even a month can be meaningless when it comes to assessing the genuine compatibility of a saddle. Sometimes, they can have a “honeymoon” period where the new saddle seems to make them feel better, but fits just as inappropriately as the old saddle in different ways.
Good luck.