Got em
I had the same problem as Jason...the J-Stiks do not just pop into place as they may have in the past. The J-Stik mounting plate is more rectangular than the X-Arcade stock sticks. My initial plan was to create some more room by sanding the edges with a drill and sanding drum, but the drums I had on hand were pretty cheap and didn't really work. Then I started sanding by hand.
Then I just chiseled out the remaining 1 or 2 mm of space I needed and then did some light hand sanding to smooth out the rough edges. Much faster and easier.
Since the X-Arcade mounting bolts are too big for the J-Stik I bought new bolts, washers, and nuts for about $2 total. The spacing for the holes was the same so there was no need to drill new holes or alter the existing holes.
All-in-all, this can be done for less than $10 and probably an 1.5 - 2 hours max.