Jacko,
If the fabric has water based stains the dry cleaning is unlikely to produce an acceptable result.
Just remember that 43% of the fibre will loose much of its' strength (70%) when wet, is very absorbent and is prone to shrinkage.
I was once tutoring a beginner who was doing a good job on a similar chair until he reached down to wipe a run from a leg, put one hand on the cushion and put his weight on it - the fabric split front-to-back
Solution No.4 would be preferable to No.2 due to its' lower pH, and unless solution dyed the colour can be fragile, so be careful with spotting agents.
