So I'm trying a different and newer way to offset a back up red dot sight. Instead of the traditional offset or the piggyback, I'm using the Parallel Mount, ACOG from Forward Controls Design. There will be an LPVO version.
https://www.forwardcontrolsdesign.com/pma-parallel-mount-acog.html
I've tried it with the TA31, wasn't a fan of the side shadow in the FOV from it. But it's definitely faster than the piggybacked RMR up top as a secondary.
However, I tried it out with an XSP2, and I kind of like it there. The riser is a placeholder until I can get gun money to buy the Unity FAST Eotech riser and FAST Omni magnifier FTC mount.
It really is faster than an offset or piggybacked red dot, or any BUIS offset or traditional placement.