hmmmm....with 2 progressives the best thing to do would be, if possible to run a tee from the hydrogen hose so it splits of to 2 hoses and attach the hoses one to each carb where u have the vac advance...then hook up the vac advance to the manifold port....i would install a valve between both the main hydrogen hose and the vac advance hose....this allow u to fine tune both vac advance and hydrogen....i would test the vacuum pressure coming from the carbs first though....i know i dont even get 1 inch of pressure from mine at any RPMs....and in that case your vac advance is not doing anything right now....but if u dont have enough vacuum from the carbs then u cant hook up the hydrogen to them....
the only pump that i know of that can run dry forever is the thermactor pump....u could use an adaptor like what i drew so the pump air pushes the hydrogen through...which might work....then u could stick it to your air filter i guess....just hope u dont backfire through the carb...thats a bit bigger explosion than just gas...but wont seriously harm anything...u might need a new filter though..hehe....
