G-B, a bit of `googling` under airborne icing tanker should get you further info,ie KC-135R-AIT,which is a USAF one; there is also a US Army CH-47D which has/had a bigger array for helos/GA aircraft ,and Cessna FTOps use a modified Citation 550.AAEE used to have a Canberra Bi8 modified with a spray bar in about `69-71 ?.I tested several helos over several winters in the NRCspray rig at Ottawa,before plunging into clouds. For an airborne tanker you should have a heated water supply,heated spray bars ,and heated and selectable droplet size nozzles,and a calibrated chase(ideally).
The water supply is also coloured with a dye marker..