Ahh, I should be more clear. I am specifically interested in what height would be required to mount the scope with the rear sight still attached ie: low medium, or high. Thx.
I used Leupold QRW medium height rings.
They'll all work with the rear sight, but because the ocular bell on the Vortex Crossfire II scout scope is so large in diameter, it won't clear the rail you'll if you use a low mount. If you use a low mount you'll need to mount the scope to the rear with the ocular bell over the forward part of the receiver opening. It might cause some eye relief problems.
There's a thread over on Scout Rifle Forums regarding this. I'm glad I read it before I ordered my rings.