Might wanna look into the DurrMaid or Rotovac mini portable extractors.... However, you'll be lacking in heat, pressure, and some vacuum.
You trying to discourage him?
Brother, you will want all heat pressure and vac you can cram on two circuits if this is gonna be your MAIN weapon, don't skimp.
You can still get around that though by using your cleaning pie. Get good chemicals, agitate, let dwell, and do extra dry strokes.
And...You are gonna do the above as a STANDARD part of your service, not some "extra".
I think you've got the right idea serving the high rise community in the bronx. I'm sure that's an underserved market. Good luck. I'm just north of you in the Hudson Valley.
I see it as an opportunity or a nightmare...it's as simple as this, you are either gonna be a Booutique cleaner that charges $75 a room in the big city and does kick ass work and have a charming personality, or you are gonna be like every other rookie and not appreciate your own labor and be selling your stuff on Mbay in a year.