Great, I now have them and look really nice on the kite.
The Delta Conyne is now finished:

I finally used organdy cloth, which is in fact a type of muslin but in this case a mix of cotton and polyester so that it doesn't shrink.
For the dowels I used a mix of bamboo canes (wing laterals and tensor) and three beech rods (for the vertical structure).
Hope it flies well and can hold up a small smartphone to make some aerial photography with GSM connection for my brother's contemporary art project...
Thanks for all the help guys.
I'll report on the flying when we get to try it.