Part of the reason for the lack of general knowledge is that most of these processes are proprietary, its basically each companies secret sauce, so they want to keep that information internal and provide retailers basic general information.
You also have to consider that most staff working at stores aren't educated on custom skates since the number of custom skates sold is very minimal compared to the abundance of customers buying off the shelf retail skates. Not to mention many employees of the larger stores which offer custom skates just don't really care all that much. As someone who has owned multiple pro shops I can tell you that not a single one of my staff truly ever understood how each custom skate differs even though I provided them with literature, videos, and even spent time trying to educate them. I was the only person who could handle these questions which is ludicrous considering I am the owner of the stores.
But, back to your initial question...
Bauer and CCM take your measurements and basically grab the components to match the specific sizing and assemble the boot. After assembling the boot they 3D print a cast of your feet and insert that into the skates. They then apply high heat and pressure the skates to form them to your foot.
How much pressure? A lot. Specifically how much, no clue, that's proprietary.
How much heat? A lot. Specifically how much, no clue, that's proprietary.
How does TRUE make their custom skates? Depends on who you ask. TRUE used to create a custom last based on your specifications and then build the skate around the last. This allowed them to make many adjustments to the skate as they are building it. It's a very hands-on process which requires a lot of work and truthfully the end result is only as good as the person doing the work. We did a ton of TRUE customs and yes, there were times we had issues with skates being too big or had a holder that was not properly aligned and 99% of the time TRUE fixed the problem. There is only one customer I can think of that we couldn't satisfy and he had significant foot issues. That customer also tried custom CCM and Bauer skates and those also didn't work for him as well.
My suggestion, give TRUE one more try to get it right. Provide them as much feedback as possible. The more information you provide the better understanding they have of what works and what doesn't. If that pair comes back wrong still then I would look into other options.