Thanks Woodja51,
That logic seems perfectly correct. And indeed it works. I was just wondering why there is no reference to it anywhere?
C Star mentioned 'why not just set C.G. directly on the pitch trim wheel'?- You're quite right and we (at least I) do. Yet most other pilots use that formula.
The result is the same however it's part of the discipline of our profession, in my humble opinion, to treat with suspicion any colloquial 'formula'/procedure' which the manufacturer has (apparently) absolutely no data on.
I'm not saying that to do so is 'wrong' (since it clearly produces the very same result) but a piece of, even semi-official, data regarding such a formula would be nice to see. If no such data exists then so be it :-)