Thanks for all the comments! Must admit I am tempted to try out the strategy Les mentioned and then using the continuous piece of covering to shrink the TE 'to satisfaction'.
It seems straitforward but I suspect that extensive trials with test-assemblies might be necessary to produce a good result without ruining the wing due to varying tensions between ribs. I'd imagine (as was also mentioned) that even spacing might be an issue with ribs being pulled in one or other direction and that getting the scallops at identical depth could be difficult.
The pre-formed wire solution also is appealing, the TE spacing would be rigid and secure with constant-depth scallops. One difficulty here might be to bend a continuous piece of music wire to such a shape and ensure that all scallops are 'in plane' (perhaps with a kind of jig??).

Don, didn't the Alb CIII that you're preparing to build have this kind of TE??

With regard to my project, its in the very early stages and due to time constraints I don't expect I'll get around to any building until sometime next year. I'm using the Fokker DI-IV windsock datafile 3-views to draft up some crude Corel Draw plans of the DIII aileron version. The DI and DII versions actually had wing-warping, what a dauting prospect to design that into a biplane!

On the off-chance that anyone has modeled any of these A/C or is intending to, I'd love to hear of it.