Karezz, I am on the cell so my apologies if I am misread. I think u are onto something with the concern if one would be enough.

For a seventy something inch square table they have used two of the bases. I bet for yours at 70 you would want two as well. Greater stability.

Off the top of my head 48" tables seem appropriate visually and safety wise for the smaller base.

Actually, I want to put a 70"ROUND glass top on the base. So I am wondering if this 24" wide wooden base would work with a larger round glass top.

We have a similar table (from Ashley) with a 54" glass top and it seats 6, and our chairs are fairly large. I would be concerned about the 70", as my grandkids have been known to lean on the ends and cause the table to tip!