I have a 1-3x Weaver, similar scope. The mediums were the lowest you could go without removing the rear sight, I measured with a caliper. I bought the Warnes from CTD for $75 I think, but I decided to stick with the Ruger rings as I rarely take the scope off and don't mind re-zeroing when I do.
I will say at 1-2.5x you're going to see the front sight no matter what through the scope, but it doesn't bother me. I usually punch paper at 3x anyway.
The Warnes are new in original packaging, PM me an offer if you'd like them..
1x on Ruger high rings:
Weaver 1-3 on the same Ruger high rings - enough clearance to the rear aperature to go medium, but not low: