The vacuum system works great, but you want to drain the system to get new antifreeze in place. My setup also has a gauge that measures line/vacuum pressure, so that you can also tell if you have any air leaks. I have used it on multiple cars including my Porsche Turbo that takes up to 7 gallons (approx) of antifreeze. Worked great there as well with remote radiators and multiple cooling lines, not unlike the setup for a Pantera.
Rick