I use light unistrut for my bayonets. For heavy things I use 2 female mounts on 12" centers. I had a dead space behind a door that was about 16" deep so I made a storage rack there.
I have 2 of these storage bars attached to uprights that can move up and down. The small female squares slide sideways so you can move them to pack things tightly.
Here is what the whole rack looks like (pic was taken before I added the 2nd cross bar above this one).
As well as this storage rack I've added female mounts all over the place. The high ones are just for quick storage in out of the way places (I have a tiny shop so no room to spare). The lower mounts get used at times too.
My bench itself has 12 mounts on 12" centers. Because the shop is only 8' wide the bench can only be 24" wide. You can see I keep 24" male extensions inside the bench mounts. When I need to work on long things or just have too much junk on the bench I slide out these extensions and clamp my work on them. I have aprox. 40 bayonet mounts all total in the shop.