In my experience, talking with the places within a drive of your house, so you can go and cherry pick a new rock shipment ... that's been best.
Keeping an eye out, while not the cheapest method, has found me a couple pieces a year that are just wonderful. Easy enough to have a tub in the basement, with about 40-50# of rock now that's just settled and ready for my upgrade in 6 months.
Water change it monthly, not much light on it ... but cherry picked arch piece, cherry picked structural piece, etc

Shame I didn't have money when a LFS here moved and brought in a few HUGE loads of rock for their new display tanks. 1000# to pick out of ... there's gotta be a few amazing pieces, whatever the source of the live rock.
Given you're working with it for a while, it's a fundamental part of how you arrange the tank ... at least for part, I'd argue for picking it out yourself - and from as large a batch as you can. There's lovely shapes of most kinds of rock - provided you can choose it, and the place has a lot.