Basically you just ignore the crew if they aren't on the same base.
Range and visibility are measured to the support weapon. Cannot allocate attacks to the crew. They are treated as a single model for all rules purposes.
You can put them on the same base if you like, or separately if you prefer. I don't own any, so can't comment on the modelling practicalities.
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From a midnight sky, there is a searing flash, a boom, a brief moment of destruction, and then it is gone.
Kabal of Lightning Strikes - Project Log
Drukhari damage output analysis