You would really be surprised at how much vacuum you don't need, especially when doing high rises. :wink:
A single large 3-stage vac is all you'll need, because you don't have to clean more than 50' from the recovery tank.
The problem with ALL portables (I own two), is that all of the components are in the same case — vac(s), pump, APO (if it has one), fresh tank, waste tank, chemical jug, wiring, internal hoses/fittings, etc. That makes the unit heavy and unyielding to move around and get in and out of your van, without ramps and an extra hand or 2. That's why I spent years designing a machine that is easy to move around, but will still give you high production, and deep cleaning. With auto feed, chemical injection, and a reliable APO (no bucket brigade), you can clean for hours without stopping!
Our electric truckmount can do what all of these portables do, and better, in my opinion (based on using our setup for high rises many times).
Since our electric truckmount is designed in separate modules, and can combine any type of change in components to fit the job (i.e., pressure pump size, heater type, etc.), because you now have 1 HWE machine that can handle just about any type of cleaning job you may encounter, whether the job is 75', or 400' from your van, or it is on the 100th floor. You still have the truckmount cleaning power that you are used to for cleaning.
One person can easily pick up each module of our truckmount, and place it onto the specially designed 2 wheeled dolly for a "one trip transport" inside. (including wand, chemicals, and all hoses necessary to clean with).
Taking this unit inside for cleaning, the LP doesn't go in, but instead a dual element electric heater 2000/2000 watt type does. Since the machine works on 1 cord only, 1 or 2 additional cords will give you steam at the wand using the electric heater.
I feed the pump hot water (direct connect), and can get steam using the 2000/2000 watt heater, using just 3 cords total, or use only one of the heating elements and use a 2 cord inside setup.
I have tried putting scores of vac motors together in all types of configurations over the years, but when all the dust had settled, I realized versatility in design would give you all the vacuum that you needed for great drying times.