Well, in a way yes.
Maybe I haven't reduced it enough.
I make the Tail Volume Ratio 0.36 (a tail 9% of total wing area on a tail arm of 4 wing chords)
But when I put it into a CG formula I reduce it, by an arbitrary amount. Three wings cause almost three times as much drag and downwash as one, so to be on the safe side I could take only a third of TVR into account.
That gies a CG at 16% chord, so I would like to revise my CG recommendation to a range of 16% to 20% of wing chord.
Alasdair