I would suggest a commercial landscape type sprayer that would come complete
with a tank, hose-reel and a gasoline powered diaphram pump. The hose would
come with standard tips and you would have to adjust. This can best be
obtained from Northern Tool & Equipment. For bc and 500 and 508 I like a
spray nozzle that I make from a brass pipe cap with a 1/8" or smaller hole
drilled in it. For silica a "cone jet" from tee - jet spray systems would
suffice for 501. Hope that helps some.
As far as backpack sprayers go I still love the Birchmier, a Swiss model
probably originating out of the biodynamic impulse...SStorch
