If going 42 mm or larger in objective size you'll need high rings with Leupold. If you have a 44mm scope now and wanting med rings check out Warne. I have 2 44mm zeiss in med warne maxima rings and bases. (1 QR and the other fixed)

Warne andLeupold DD's have both been excellent from my stand point.

I should note I don't own an omega so I may be wrong but I have yet to find a rifle where leupold meds would accomidate the larger objectives.

Good Luck