Slab jig version 2.0 is in the works. On the original I used a deep 1/2 wide straight bit. Because it was long it cleared the 3/4" thick bottom “runners” of the jig easily. But being primarily a side cut bit as opposed to a bottom cutting bit and so narrow it required many passes and was pretty rough, requiring a bit of sanding.
So I bought a bottom cutting surfacing bit that is, if I recall, 7/8ths wide. It’s made for a cnc router for this exact purpose, make flat surface cuts. But it is a very shallow bit and at max depth of the router and with as much shank as i dare leave out of the router it just didn’t clear the 3/4" runners enough for my liking.
So I got some scrap L bracket shelving stuff from work. This will replace the 3/4" runners with about 1/16th inch metal. That should give me enough clearance. I also made a plate for the router that fits between the L brackets to guide the router better than I was doing it. I also bought a package of two wood rulers from the dollar store that I will inlay into each side so I can adjust the height off the table without the need to measure with a tape measure. When I get it done I will give you guys a better look at it.