Sticky back paper on inside of PVC pipe sections.

Alan, that is one cool idea and I thank you for sharing it.

paul - on the vector - you want to pay particular attention to the LE shape - there is a template on the plan - cut it out and glue it to a block of balsa - then cut to shape - glue sand paper to the internal face and use that as the shaping tool.

I will take a photo of my one when I get the house unpacked.......

Use a razor plane to get the contour close, then "shoeshine sand" for perfect contour.  The technique is to hold the wing leading edge up, then grab a length of sandpaper at both ends and work it back and forth across the l.e., holding the ends as close to the wing as possible.  The tension on the paper will hit only the high spots and leave the low ones until it is perfectly even.  No hardware required!

I make these jigs for shaping the L.E. on some of our kits