I don't understand the problem. We use the R1R1, R2R2, r'r, r"r set simply because those are most readily available/abundant from our reagent red cell sets.
C: positive control- r'r , negative control- R2R2
c: positive control- r'r , negative control- R1R1
E: positive control- r"r , negative control- R1R1
e: positive control- r"r , negative control-R2R2
I know there are other options more readily available within the general population, and likely our inventory too... but then there's a conundrum. How do you test units you hope to use for controls without the method being QC'd in the first place? It's a tight cycle to upkeep for a small group of generalists. We don't have full antigen information disclosed from our blood supplier either.
Personally, I can use my own blood for several of the controls... but I don't want an extra monthly poke! Haha!