You're right Peter. The bolt holes are 1/4" nc thread so it is actually pretty robust. I used tapered head screws so alignment is the same every time.
I started by squaring up the plate in the mill. It's a piece that i got from Al in Cochrane when he was getting ready to move. Then i set it upright in the saw and cut the slit for the blade and made the measurements for the blt holes off the slit. The pictures show i set it up and i slit it 1/2 way across.
The picture shows the finished part but this was the first operation after squaring the plate. Since the screws are always going to stay with the plate i countersunk the holes on the bottom and put o-rings over them to keep them from getting lost.
It stores in the bottom of the saw cabinet.
I have one of those fancy Incra mitre gages for my table saw but it is 5/16" thick so i couldnt mill the fence deep enough to use it on a 1/2" thick plate.