More details needed but often stone tops rely on gravity to hold them in place unless there is a large cantilever. Something like silicone will hold it in place without adding thickness. More details needed though!

Thanks for your prompt response. What other details do you need to know?

We have a marble table top on a steel base. Gravity holds it in place. But mine is not inset as you describe yours. The table top is very heavy and has never shifted even though it is not attached. We have moved once since owning the table. It takes about 4 men to move the table top. Can’t imagine it being moved if attached to the base.

I think if the base is made to have that top sit into an edge or lip you need no silicone at all. I have had marble tables for a long time with no need for any kind of adhesive to hold them. I think we do need to see the design for the base my understanding is it is only sitting on the end parts not the sides

" Installation of a slab into a steel frame is going to be very very risky for someone to lose a finger."

Nonsense. Set 2x4s across the inner frame. Set the marble on the 2xs; plenty of clearance for fingers. Raise the marble from underneath while a 2x is pulled from one end. Repeat.

I wouldn't risk any adhesive (unremoveable bleeding) or mechanical fasteners (cracking), especially on a trapped marble top.