Oohh ,if you talk about the resolution, again, should you be worrying that much? I don't think so, because you're likely going to use NEMA 17 stepper motors(1.8deg) and you can do microsteps. Even that, depending on if you use belt or string then it may or may not matters. But keep in mind that your nozzle will likely cripple all movement and you will have srhinking that outcomes when speaking of error/tolerance.

When I was mentionning overconstrained, I did not mean on a 3D cad perspective, but what you mentionned about the number of rods for each carriage. Because having myself with 2 Delta self assembled, I see flaw where the hot-end mechanism wobble.

I designed my laser burner printer based on 3/8th rod I found from inkjet printers, the linear bearing cost for this typical dimension cost way too much and I have to scrap the whole design. I decided to downgrade to 8mm shaft and use LM8UU bearing.
The cost for the linear bearing drop from 15 to 2-3$/unit.