I recently installed one of the UM/SRS pic/spartan short rails in the forend of a Stockys VG for a Howa mini. I installed it using the factory installed t nut for the sling stud, then had to drill one 3/4” hole forward of that for the Spartan cup. There isn’t a lot of meat up front in those stocks but it worked well. I used JB Weld.
Because the radius of the stock doesn’t match the radius of the pic rail perfectly I came back, masked everything off and put epoxy to fill the gap on the edge of the rail and stock. The t nut has epoxy on top of it and the rail is glued. Shouldn’t ever have a problem with it moving. Rifle is a 22 arc so also not a big kicker.
Second pic shows the gap filled. It’s not gunsmith quality work but completely functional.