I took two scrap pieces of maple and cut them to fit the miter slots. I sanded and filed them until I could move them up and down the slots without any problems. After that I glued that long piece of wood to them inside the slots to make sure eveything was flush (I put cling wrap between the maple miter bars and the pb so the glue wouldn't stick the whole thing together)
The next part was to fit the circulat saw under the table. I didn't want to cut any holes in the saw since it didn't have any extra holes or screw holes for jigs. So I opted to make wooden clamps. All I did was make 4 holes in the table slightly recessed for 4 bolts and nuts and stuck the saw under it. Clamped between two pieces of wood.
I used a large set square to make sure the blade was flush. I just moved the saw from under the table until the blade was flush then tightened the nuts on the wooden clamps. That was it. I clamp the ON button to operate the jig since theres no way of keeping the motor running if you don't hold the button.
On this pic I've got a piece of scrap waiting to be slotted. The way the jig works (like all table saw jigs) is to leave a small pin inside the fence that fits perfectly in the holes of the fret slotting template. Tape the template on top of the fingerboard blank with double tape. Hold the piece of wood on the two sides of the template with the fence pin resting inside the first hole on your fretting template and cut the first slot. For the next slot, move the piece to the next hole in the template and do that until all slots are cut.
Here's what the scrap piece looks like once I'm done. Disregard the two crappy slots, they were done first without the template.
BTW if I had to do it again, I'd use aluminium bars for the fence/miter slots. The maple has a tendency to bind on the sides on humid days