I prefer horizontal. I have experienced more issues trying to keep the reticle level while tightening vertical split rings, same with the original Weavers w/AL bottom, steel-strap hook/screw tops. Hard to keep those old school Weavers level while final tightening too.

Last edited by horse1; 07/27/21.
I can walk on water.......................but I do stagger a bit on alcohol.