Not sure what your LFS considers "premium". I wouldn't go spending a lot of $$ on the LR. Find pieces that will fit your planned rockscape and let it seed what you currently have in there. Coralline Algae will come in time and it will all look like "premium" rock.
What is your LFS asking for their rock? Where is the rock from? Fiji is typically less expensive than say Pukani or Tonga.
/Jeff
I'm not sure of the source. I only picked up 5lbs to seed, so it was not bad financially. I'll post pics when the light shows up.