I ordered 3 different types of seals and sizes to find the best fit. My canopy skirts are exterior to the fuselage skin and overhang about 3/8 " with <1/16" gap. After the test program, I decided there was no need to go through the hassle of trying to get the best seal and never installed any. I have never felt any air at all in the vicinity of the canopy sides, including when flying around at below 30F temps in the winter.