Dickeybird - I'll go for the 'D' box and filmcovering - love seeing an open wing structure overhead. Had thought about using a geodetic structure a'la free flight days. This would reduce covering sag considerably and give greater rigidity, maybe with a weight penalty. MH-Aerotools is a fantastic site, should be compulsory reading for all modelers. I'm sure I could smell Nitro while reading it !

Bruce - Charles River R/C. Spent all day Wednesday printing and then doing a glue and stick job to produce the Mark Drela creation. Interesting to read how the design on some of the AG airfoils has taken into consideration covering sag. All those tips and guidance notes I shall follow to the letter. Good tip on sanding the sheeting before applying ! Leading edge sharpness....hmmm....I've seen a thread about this very topic - will have to read and inwardly digest that one.

Probligo - Have joined the allegro - lite interest group, should be an education in reading about other modelers experiences with this model.

Many thanks for the guidance in your replies.
DavidO