I use Old Coots awning pole supports with my 2809W, they are great. See this thread link...
Awning pole hold down kit
I also use a set (two) Camco 44531 adjustable stabilizers attached to a board that I place under my front steps (board cut to fit under bottom step cavity). It has to be adjusted up and down depending on the level of my trailer at a particular site, and I sometimes add boards under it in extreme level situations. See this CW link...
Adjustable Stabilizer - Camco 44531 - Stabilizing Jacks - Camping World
FYI - I found them at half the CW price for $15 each at Wal-Mart.
Edit - Oh, I take that back, I think I'm using Stromberg Carlson stabilizers with my Windjammer. The Camcos were for another trailer.
I don't use de-flappers with my power awnings. Good to see you are getting out with your Windjammer. I just got back from a week near Ft. Davis and Big Bend. Heading to Frio River area next. This Bazos Valley pollen is making a real powdery mess on my trailer. Stop by, I'll show you the installed poles or the step stabilizer.
+ 2013 Rockwood Windjammer 2809W
+ 2008 GMC Sierra Crew Z71
+ 2002 Ford F-250 7.3L 4X4