DD flutter
Cappy,
As long as you use strong enough servos, heavy-duty hardware and 4-40 rods you shouldn't have any problems. Remember the airplane is covered with UltraCoat in one continuous piece on top and bottom. You tuck the UltraCoat into the hinge line with a trim iron.
The only time I had flutter was when I used cheap servos. I started out using FMA high torque coreless servos. After about fifty flights or so with the Jett FIRE 50 I got flutter. Turned out the bearings and gears were shot. I could wiggle the servo arms back and forth 1/8" even with power on. After switching to JR 8101's the flutter went away. They are high torque, coreless, nylon geared servos with wide-spaced bearings.
You can probably get a way with cheap servos for a while but over time I think they will get sloppy on you. Best bet is to go with the best servos you can afford right off. If I was doing another Diamond Dust I would go with 9411 mid-sized digitals.
So far the 8101's have worked out well and are a bit easier on the wallet at 69-75 bucks apiece.
Good luck with your Dust. When it comes to max wow and fun factor in RC you can't do any better than a Diamond Dust or Whiplash.