On Friday, May 29, 2020 at 6:51:16 AM UTC-5, Hawk wrote:

You're correct, I'd need to sand one or the other. I am able to smooth
the edge of the granite and obviously the wood to get the best results.

Other issues you'll have to tackle:
1) My marble slab is 1/2" thick. Your slab is 1", twice as much surface to work on, twice as much surface to get right.
2) You'll be installing your slab repeatedly, checking the fit as you go. Placing the slab in exact position each time, then having to remove it will be aggravating, frustrating. Anticipate this install-remove and how you'll accommodate the ease of insertion and removal. Your slab will be awkwardly heavy for ease of maneuvering the stone. Finger holes, finger-like holes (in some capacity) underneath the base/support will help with this maneuvering during repeated fittings.

Another option for other (small, smallish) tables is to have a trim around those edges. You said you have other slabs.... for other tables, I assume. A trim edge is not so bad, no one will know if this is part of the plan. A trim won't look unsightly or out of place. As mentioned, a caning spline would work well for inserting a trim feature. The issue with a cane spline is that you'll need about 3-4 layers of spline for the 1" thickness of your slabs. Cane spline is about 5/16"-3/8" thick for a 1/4" wide spline. That is not a problem, as spline is inexpensive and very easy to install..... and can be stained and finished. It is soft enough to conform itself into an uneven, irregular space. It's easily cut with a razor knife. Should this spline option be a consideration, I get my caning supplies from Franks Cane and Rush Supplies. Here's a link to his spline size and prices. You can, at least, get an idea of spline dimensions and price. Example: 50' roll of 1/4" wide spline is $11.25. Scroll down to Reed Spline. There may be a caning supplier near you, as well.
https://www.franksupply.com/caning/p...ng.html#spline

Hope this helps.
Sonny