Ye, I will probably use a mix of @player grenades and swap between windows and use grenades with something like:
/use [@cursor] Iron Grenade

Should only take half a second to a second to start throwing it when switching and Iron Grenade is really cheap (1 iron bar, 1 heavy stone, 1 silk cloth for 2 Iron Grenades I think).

A little hard to pull off without stopping to cast spells with every character for a second, but might be doable, especially when using it from healer.