You should try to get ahold of Don Gordon at the western command website. (I don't have his email with me at work) Don is in Victoria B.C. and has had his C8 down to Portland at the MVPA convention. His Partner Katrinka, made a beautiful canvas back, mud flaps and all the canvas bits. He could also send you the measurements for the frames.
I'll try to find a picture for you.
http://the-hole.com/WCMVHS/image-mir...G_0015_JPG.jpg
Here you go!
We will be at the Arlington Airshow in July, Don too I suspect.