suggestions on setting up new mesh or WDS

Hearing about the new mesh package that is out I have once again been thinking our downtown hotspot we are implementing.

1 idea 3 to four radios with 120 degree antennas at four corners of square with a to the back hall and b on 4 separate channels and ssids

2 try a wds set up but from my understanding they have to set up in a line and I think that would cause issues

3 new mesh system but would I be able to use the a backhaul

Our back hall is about a block off the square on a 4 story building with 25 foot mast both a and b available at that point

Any suggestions??