If I'm reading this correctly, you want to use dispensing systems to apply solder paste to PCBs for low volume assembly/prototyping. I should stop you there, use a stencil, its cheaper, quicker & more effective. Solder paste is not a simple dispense and anything but the most high end systems are not capable of even coming close to a basic stencil setup, as even a low end user you will encounter devices that time/pressure or Archimedean screw dispense methods cannot dispense accurately enough. There is a reason the market is not flooded with cheap robotic dispensers for low volume manufacturers wanting to avoid buying stencils or the time associated with getting them. There is also a reason solder paste is barely a footnote in the types of fluid those machines dispense, because when they are its as a top up process or rework. If you want to be cheap or flexible, you'd be better off cutting stencils form OHP film with a vinyl cutter, crappy but effective for the bulk parts.. allegedly.