Hi Michael,
To ensure even distribution of liquid to each target well from a parent channel during a dispense on the fly step, the key step parameter is X speed (the speed at which the channels will traverse labware during shot delivery).
The dispense rate during delivery is modulated by the liquid class, so the X speed should be configured such that X travel and plunger/dispense movement end at the same time (at the end of the plate). If the X speed is too slow, then the dispense will be complete before reaching the end of the plate. If the X speed is too fast, the channels will reach the end of the plate too early, and the channels will over deliver the remaining volume to the final set of wells.
An X speed of 0 (auto) will trigger VENUS to auto-calculate and apply an optimized X speed for the dispense and labware. Of course, this is ultimately a theoretical starting point and may need to be fine-tuned for different liquids and liquid classes.
Regarding using a loop to dispense to multiple plates, once your dispense parameters have been tweaked to consistent and robust performance (based on the above), I would program the same way as any other aspiration and dispense loop which use single steps. The specific logic and sequence handling used will vary per your scenario/requirements. In your case, each iteration of the loop would process a single plate.
Thanks.
-Nick