Hi Janematt,
Up until this arvo we had only been using the zippered canvas windows, up during the day for light, and down during the night for darkness. But a big thunder storm has decided to roll into Crescent Head late this arvo and still continuing, so the clear PVC windows have now been put up. I'm so glad we have these canvas bed fly's, even though its windy and absolutely pouring down with rain, the internal canvas and beds are dry as a bone! So we've now used all combinations with these fly's and all is good for us.
Not sure what you can try if your having trouble with flapping and noise?
Have you got it pulled nice and tight around the sail track, so the corners are tight? Then again nice and taut where it attaches they your Expanda with the press studs. I'm wondering if yours might be a little slack and then allowing more movement and flapping. Might be worth checking to see if you press studs can be moved to make the fit more taut!
If I think of anything else I'll let you know!