A vacuum, a simple portable for rinsing and a 10 inch
CRB for scrubbing. Vacuum the carpet, put down your pre-spray, scrub with the
CRB and rinse with the portable.
Get a couple blowers to dry as you go and you are going to get good dry times and get better results than most using a truck mount.
If you did all that and rinse with a truck mount it would be faster and you wouldn't need a Chiropractor. Your back will tell you when it's time for the
big truck mount...and the phone ringing with new customers...when you are busy enough to justify it...go big.