Vertically split rings can make you wish you had a 3rd hand.
Have a look at this video from Warne on how they mount their rings. I have a couple sets of Warne and a set of Talley's and used this method on both.
The video is for a Weaver base so ignore the recoil lug references.
It's a bit different for a rimfire with dovetail, but at about the 2 min mark he gets into the tightening sequence.
This general method has served me well.
https://www.youtube.com/watch?v=v2kmlIgYKAQ
lol at the Warne rep calling their rings a 'contraption'.