https://www.brownells.com/optics-mo.../34mm-mountain-tech-rings-prod97243.aspx

Go with lows.....

Here is mine in NF mediums.....only pic I could find on my phone. However since your in a chassis I wouldn’t worry too much about getting as low as possible. I believe mine is just under 1/3” gap but tough to see that in the pic.

[Linked Image]