we didn't consider quartz so I'm not familiar with the process, but when we did our granite we went with our fabricator/installers to 'slab yards' where we had to hand pick our slabs. we weren't able to consider selecting any unless there were matching slabs on site (no ordering extra, might not match) sufficient to do our job. is this not common elsewhere?
This is what we did. Picked the specific slabs that would be used as well as how we wanted the cuts done.
Marble would be too fragile and take too much upkeep for me.
I didn't care for the uniformity of quartz. I wanted the more natural look of granite with some color variations.