I have the advantage in that I work in a Reference Laboratory in London with an enormous stock of units.
That having been said, we would give c Negative E Negative blood to all R1R1 patients with a haemoglobinopathy, or an auto-antibody (or any other condition that means they are likely to become transfusion dependent) and to females of child-bearing potential, even if they have not made an anti-c or an anti-E, as a sort of prophylaxis to stop them making these specificities (although of course, "naturally occurring" anti-E-like mimicking specificities still occur).
Any patient that falls outside this, we just give the cognate antigen negative. Remember, the vast majority of patients who receive a transfusion either die within 12 months,or never require further transfusions throughout their lives, and so it really isn't worth giving R1R1 blood to these others.