David, there was a build thread on here a few years ago by GordonMc, have a search for it as there may be stuff on there to help you.
The ribs may be sized for the thickness of Proskin so you will probably need to remove some edge from them
Wren pipes are thrust augmenting rather than plain parallel, and I believe they now, at last, offer the option of a twin wall.
Harry
Thanks, yes I've read GordonMc's thread, his plane is lovely, I can only hope that mine is half as nice!
...I'll be powering mine with a P80 which will mean about a 70% power to weight ratio - which was still higher than the originals 50% power to weight.
The ribs appear to actually be too thin for proskin and the instructions suggest building a kind of fillet so that the thin wing matches the thicker fuz rib. I wonder if the kit was originally designed for balsa sheeting as the wing seems to fit better with sheeting than without - the extra 1/16” helps with the gear clearance as well!