I'll look into tapered nozzles.  Good idea.  One local supplier I regularly deal with that handles camlocks, nozzles, hosing, fire gear, safety stuff etc doesn't stock them, or at least they were never mentioned when I asked about different nozzles.  Doesn't mean they can't get them though.  Camlocks will be essential if we get into swapping nozzles.

Fixed boomless nozzle-  we have holders on the burners for their water nozzles pointed to the side so that they can lay down a water line on the outside of the burn path to make things damp and slow down the fire when burning firelines.  Those ones are adjustable (regular garden hose nozzles).  Might be worth looking into adding a dedicated boomless nozzle though.

Adding soap to the water- might be an option if we used an injector after the pump.  I've had some experience with transfer pumps pumping foamable liquids and having them not be able to suck water up an empty intake line after the pump gets filled with foamable water (chemicals when I tried it).   Maybe just a little bit of soap in the tank wouldn't cause a problem?  Hate to need a refill NOW NOW NOW and find that the fellows had to drain the pump and prime it with fresh water.

 Thanks for the input.  Good ideas.