[DesertRatTom]

You might also want to check out some tiny setup gadgets by infinity tools, just for miter lock joints. See pix. You mark the centerline of the material, line it up with the mark on the magnetic jig, and it cuts an accurate lock joint. Comes in two sizes to match bit for different thicknesses. Very helpful.

You might want one of these center finder/marking devices. This is from Rockler.

 

[DesertRatTom]

One last thing. I like to use 3/4 inch chunks of MDF to push parts through the bit. That and a tall fence make it very easy to keep the workpiece square to the table and bit. The bit will eventually tear up the corner, but if cut square in the first place, you just lop of the torn up edge and use the rest. Gives good control, keeps the piece square, acts to stop tearout.