A bit late to the game here.
I’ve used one from each of the above options.
Both fit and work just as well, I was unable to identify any difference between them.
223 CTR
6.5 CM Tac A1
Both great stock choices. For me as I’m prone to be a bit clumsy, it would be the GRS, however the Form, is a thing of beauty and if your the careful type well worth looking into
I’ve got my t3x CTR 223, in an Oryx. It runs the metal ACIS mags great. I also have an MDT mag that fits very well, but it’s a 10 round so not used it yet, lol