Re: adjustable gas block
Assuming you want adjustable, meaning set once and leave alone, and not selectable, then the PRI is a no brainer. Just make sure you get the correct barrel tenon diameter.
Be sure and loc tite the allen where you want it once you decide how many turns in our out you want to run it. Also loc tite the allens from underneath that hold it in place if you don't want it to shoot loose.