I have some of the PRI .936" Lo-Pro blocks.
Make sure they are the correct ID. One out of the first 4 was .943"
They have an open ended gas tube hole.
If you have the means you could cut the block off your gas tube a little ways in front of the hole, tap the front end of the gas block hole, and make a piloted set screw that would fit inside the gas tube to adjust your gas.
Sounds simple right
Gettin at it from the front might be tough depending on your setup.
Nick