Thank you very very much for that information! Yes, 5.8 kilos for a 1/6 scale CIII, is very impressive. So the 6-7 kilos total weight I proposed seems like a good ball-park figure. In my opinion, 8 kilos would start to be on the "heavy" side for such a early aircraft. I would very much be expecting to get a "trainer-like" wing loading, rather than something more appropriate for a fighter (or worse yet, WWII warbird).
The following suggests that 20oz/sg.f would be appropriate for sport models.
http://www.csd.net/~cgadd/eflight/calcs_wingload.htm