The way some of them grid drains are constructed the sinks won't drain properly, they drain slowly then when enough head pressure builds up it dumps. Not sure if maybe the openings in the grid don't equal the cross section of the drain as required, but Ive run into that problem before.
Regarding the the picture if the furthest sink was within 3 1/2 feet I would stack the tee's and wet vent the lower drain.





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