Klaus,
when you say "plane down" the wood, do you remove wood from the thick side or the narrow top?
Removing from the top would be much easer of course

When you apply epoxy before glassing. Do you let the epoxy dry, clean and sand, or do you put on the glass before the first epoxy layer have hardened?
Have you noticed any lasting twist/corkscrewing of the battens if you leave them in a rolled sail?
What is the weight like compared to foam/glass battens?
How lang have you sailed with wood/glass battens (durability)?
Wood is not a uniform material so this will never lend itself to mass production with consistent results. However I would like to try this myself! I think it might work out very well!
One small thing. If you tie your battens in the batten pocket it might be good to drill the hole oversize, fill with thickened epoxy and re-drill once hardened. Otherwise you might get cracking and water/moisture seeping in there.
Thanks for sharing!