When I used the extractor, I pre-sprayed the seats and/or carpet with HydraMaster FabricMaster Heavy Duty Upholstery Pre-Spray. It has a high PH (around 11) but is self-neutralizing. I would brush the material a bit and then extract with HydraMaster RinseOut (PH around 6). If I didn't have RinseOut, I could use clear water since the upholstery pre-spray is self neutralizing. This combo is designed for professional upholstery and fabric cleaning using a hot water extractor, doesn't foam up, and leaves no residue that will attract more dirt.
With the air chuck, I pre-sprayed with diluted HydraMaster, brushed, and then used shop vac to remove whatever moisture it could. The air chuck would come into play around tight spots like seams and rear seat seatbelt pockets.
To be honest, if the car isn't completely trashed, the extractor is a good tool on seat bottoms. Seat backs always seem to require extractor gymnastics in an effort to hold the nozzle so that it has good contact with the seat and/or that the rinse liquid doesn't just run down the seat when you pull the spray trigger.
Where I've found that the extractor falls short is with really bad seats. Just spraying and sucking doesn't get the really bad stains and you can't get into tight areas. I'm simply replicating what the Tornador Black Cleaning Gun does but without a big awkward tool.
I don't claim to be the ultimate expert on this. I'm simply sharing what I learned after eating a big slice of humble pie when someone with more experience that me showed me how it can be done much faster and better than I was doing it. My choice of chemicals came from time I spent working with a professional carpet cleaner.
Bill