curiosity got the better of me, so i measured the vac on my hoover.
its not the most powerful in the world but will suck on to palm of hand, bad news as suspected only -46mbar(even a very good mega hoover double vac maybe?-90mb), if i remember right it took at least -100mbar to even see the actuator lift lever off rest position and onto -600mbar to reach stop screw.
with a short piece of pipe(couple of inches) a 100cc syringe should be plenty to pull it enough to see it move a fair bit , 250cc even better.