Hi Klinger
During your inspection, look VERY CAREFULLY for signs of pilling, especially in TV shuffle and traffic areas. Bring it to the customers attention before you start. When cleaned, it will be more noticeable.
Unless you have very soft brushes, mechanical agitation may be too aggressive. So detergent may be preferable over microsplitting. Make a judgement.
Use a paper and pencil to find the pile direction. It may be at 45 degrees! Agitate in this direction only whether mechanical or brush.
If there is potential with this carpet for cellulosic browning, use an acidic rinse (preferably in-tank as it does not then affect drying time).
Apart from this general advice, any specific issues may need to be addressed individually.
Safe and happy cleaning
Ken