I don't have experience with the Jackson custom (rapid or full), since I'm able to wear a Jackson stock boot. I do have a caveat about their fitting process. Advanced men's figure boots generally are not kept in inventory and need to be ordered. I ordered my first pair of Jacksons in late 2014. They were fitted the old-fashioned way: a series of foot measurements and a series of tracings. Of important note, the measurements and tracings were taken twice: once when I was sitting (non-load-bearing) and once when I was standing straight (load-bearing). The measurements and tracings were sent to a Jackson rep, and they shipped a size 8W. With some heat molding and punching, the fit was good.
I ordered my second pair of Jacksons in late 2022. This time the tech had the Jackson optical scanner. With this unit, the feet sit on top of a glass platform, tilted up vertically ~45 deg from horizontal (floor plane). Scanning was performed when I was sitting only. The computer spit out a stock 8M. I didn't believe it (the tech told me the fit of the 2022 Jacksons should be close to my 2014 Jacksons). I asked the tech to order 8W instead. Again, with some heat molding and punching, the fit was good.
I believe the discrepancy results from the following. At one time, I had normal arches, but they are now fallen. So there is a significant difference in shape and width between sitting and standing positions. The old-fashioned fitting picked this up, the new optical scanner did not. So if your tech has the Jackson optical scanner, ask him about his success rate.
My tech told me that he had great success fitting Aura customs (when they were available). Aura also used an optical scanner, but three sets of scans were taken: sitting, standing straight, and standing with bent knees and ankles. As Mr. Spock would say, "That's logical."