A regular wand with a holed glide would probably be a good combination of ease of use and not leaving very distinct wand marks. But probably a bit excessive to go out and buy a new wand for one carpet clean!
I would just stick to wool safe practices and do a test area. Maybe get them to agree to you doing a test clean of a couple of square metres in a corner or under a sofa for example. I would find the best direction in which to wand, and maybe just do backwards strokes to keep the pile all in the same direction. Make sure you use acid rinse, whack an air mover on it and groom immediately. Finding the right grooming tool to set the pile correctly will probably be quite important.
But this all depends on how much silk content the carpet has... if it's 5% or something silly you won't really have any noticeable texture problem from the silk element. Also depends if the silk element is blended into the yarn or used as a separate yarn.
I definitely would not tackle the whole carpet without doing a test area first if it seems likely you could damage it.
Thinking of alternatives to HWE, bonnet cleaning is probably a no-no. A dry compound clean might be OK in terms of risk but even so it would depend on the machine and brushes uses as to the risk of physical damage. So HWE is probably the best bet, as long as you can do it safely.
I'd be charging well for this
