I had the pad printed out and used it on KOF 98 with GREAT results!
Excuse the vids as I'm playing with one hand and recording with the other, but you can clearly see me busting out fireball, hurricane kick and dragon punch motions without the pad coming off!
Furthermore I used regular tape that I made small loops with to stick it to the controller (as the double sided tape I had wasn't very good and didnt stick well) and yet I was still able to use it with great results!
Trying to see if I can find a cheap left joycon as I may actually glue it to one since you could easily swap it with one that didn't have the dpad of you just needed the buttons.
Either way, here are the two vids!
Thanks again, Faiz, for this awesome dpad solution!