Actually I was thinking about both, I'd like to find out how much groung effect (if any) could be considered for any help lifting up the load of water and afterwards the effect of the downwash during the drop, all that to find out best distance to hover while picking up the water (you know, belly hooking, ventral tanks, long/short lines ...) and best height for the drop not feeding the flames with more oxigen.
Now I'm going to need some time to undrestand all that has been said so far
Thanks a lot and buen vuelo