So, if Pro 2 freehub bodies are susceptible to excessive gouging from cassettes, surely a singlespeed conversion would make a right mess of it?
But plenty of people must do it? Should I just get on with it?

Get a sprocket with a wide base – have a look at Charlie's website for options probably

I put a steel freehub body on mine. Still marks but nowhere near as much. Just a little bit heavier thats all. As i now run it with wide based sprockets i'm thinking of going back to the ally one.

Use the pro2 trials.. steel body and builds a strongererererer wheel plus sounds class.
i bought a whole wheelset for 120 second hand with pro2 trials hub..
The rims that came with the hubs are worth 50rrp alone.
Ebay folly will occur soon.