I pondered the gaps between the canopy skirt and the vertical tubes in the canopy framework for a few days, and finally decided how to proceed. I measured the gap at each hole, and then laid up a bunch of flat pieces using between one and seven layers of fibreglas cloth. This gave me a wide variety of different thicknesses to make spacers from. I needed spacers from 0.025" to 0.150" thick.
I first did a test with three spacers to be sure that the concept would work. They bonded well, and the fit was quite good.
I used some 1/8 inch bolts and washers to hold the spacers tight to the skirt while the resin cured. I was afraid that I might have trouble getting the hardware off, but the hardware for the three test spacers popped free fairly easily.
I fibreglassed all the spacers in place this afternoon. I'll remove the hardware tomorrow morning before the resin is completely cured. I'll test the fit later in the week. Tomorrow I'll work on tidying up the wire bundles, I think.