well first off low dovetail rings are hard to find and if you found 6 different pair there could be 6 different heights from the bottom of the ring to the mount area
the other problem is do you know where you want your scope already, lows could be to low and mediums could be better but again different rings different heights
but the differences are small in any case
so a 44mm bell on the scope, that would more then like need a medium ring
I have a box of rings and mounts that would choke a horse and many of us do but I bet if you picked a scope and called or email the company that made said scope they could tell you
or just buy some rings and I would start with medium