pre spray with Prochem Fab Restorer and extract with Fab Clean (Fab restorer for heavily soiled areas). or prespray with Chemspec Prekleen (heavily soiled areas and extract with Powdered Extraction Upholstery Cleaner. As above this is the standard of suites you will get. I would also suggest a good pre vac first, you never know what you can find down the edges of the sofas. Good degree of agitation with soft brush and dwell time, this is all after of course carrying out usual pre tests.
One other point worth mentioning make sure you brush the pile after each extraction clean with a horse hair brush, not the same you used for agitiation just to make sure you have removed the tool stroke marks.
Regards
Darren