I'd appreciate some help figuring out the best power to make the balance lens for this patient. It's something I usually leave to the lab, but this time it falls on me and I don't have the lenses in hand to visualize the differences.

RX is
OD Balance
OS -6.25 -0.50 165

We are doing orma in the rt and 1.67 in the left. As the 1.67 is 30% thinner than orma I was thinking a -3 would work in orma for the rt. Thoughts?