I used 8/32 bolts, head on topside of panel, but countersunk into the wood, then covered with wood filler, sanded down smooth and painted. On the backside, I countersunk the nuts to hold the bolts in place, then more nuts to hold the joystick.
But I like the idea of the T-nuts, you can countersink them, on the front of the panel, wood filler over them.
These would require less work, and Im all for less work.
Here's a rough sketch of how I did mine: (I did this quickly with mspaint, so excuse the dimensions):