Cc'ing will give you the chamber volume. Measuring the depth of the chambers give you the quench distance information. You want that distance to be as close as possible from one chamber to the next. Then comes polishing all of the sharp edges and possible hot spots out. You can get pistons much less than 800 bucks with the KB Hyper......but your machinist doesn't like those. And I get that. But he needs to understand that's not the piston's fault. If he did the machine work and filed the rings (or didn't file them) it might be HIS fault. And THAT is something you should think about.
I normally never recommend quench in situations like this because 1) you're somewhat of a novice (no offense we all start somewhere) and 2) you're on a budget. Machining CORRECTLY for quench costs extra money.
Lastly, there's no amount of quench in the world that can save you from detonation in stop and go traffic when it's 95 degrees outside in high humidity if you're on the ragged edge. That's another reason why I don't recommend quench for a street car. You can end up not having a very streetable car if everything isn't perfect.
.....and when have you known anything to be "just perfect"?
Go along with these guys if you want to. It's your project, your money and your choice. But if you end up with something that you can barely drive, it won't be my fault.