I’ve been eyeing the straight jacket, glad it was brought up, that was going to be my suggestion, though I have no experience with that bag specifically. Kifaru does make great gear.
There’s a recent thread about the ARC rings, lots of positive feedback.
I have a set in 35mm.
https://www.longrangehunting.com/threads/m-brace-rings.307283/
They are based out of Washington. The bolt torque is 55 in-lbs if I recall correctly.
I like them so far, easy to set up, just have to make sure the pins are even on both sides before you torque everything down.
I read a lot of positive posts from different forums prior to purchasing mine...