I think you'll find that the majority of professional carpet cleaners are equipped with a wide range of systems, equipment and tools and can use whatever technique suits the circumstances, including combination cleaning.
If you're determined only to use LM then you need a day out with Hector or Jason Lawal so you can get an idea of how to deal with the wide variety of soil conditions you'll come across in the domestic market.
This business is all about results, get the right result and you'll begin to build a list of loyal customers, get it wrong and you'll never se them again which means ever more advertising and the costs that go with it.
Simon