I'm afraid Festool domino is not in the budget, but I am thinking about dowels.
The bench slab is down to 47" long. I'm thinking about only going with two legs and mounting them 6" from each end. I really like the look without a shoe rack. If I proceed as pictured, can I get away without a stretcher? Obviously, I have much to do with finishing the legs and slab still, but just wanted to give an idea of what I'm thinking.
I'm planning on routing out 1/2" slots for the legs as George suggested. My neighbor thinks I should add dowels to that, but with only 1 5/16" thick, I don't know how much I could get away with there. The other thoughts are to rebuild legs with 2 notches (not sure the proper term) per leg that would sit flush with the slab itself, end grain showing. Or maybe I could bore down into the existing legs to install walnut pieces that would meet the slab. Otherwise, I'm wondering if I could stick a stretcher right beneath the slab.