You'd need to contact Leupold and speak with their techies directly but IIRC, a .0067" dot will subtend approx 5/8 moa @ 20x in your scope and they can put that in.
If you want a slightly smaller dot with more horizontal/vertical reference, you can ask for their Leupold dot on the converging wires -- which is IIRC .0060" -- and that will subtend approx 1/2 moa @ 20x.
I've had Leupold put both of these dots in 6.5-20X scopes. Unless they've dropped some reticles from the line, they should be available...