engine? 4 a Cloud Dancer kit
I built mine from the ACE kit some 8 years ago. It still flies well on a 46FX. I have never experienced any flutter problems, neither before or after I modified it with two aileron servos. Two aileron servos are not really needed on this plane either, you should be able to achieve nice axial rolls by providing some mechanical aileron differential using only one servo.
I think the CD might be a tad underpowered with a 40 LA. If you are going to do any kind of aerobatics I would suggest a ball bearing 46 instead.
Oh, and if you're flying from grass, forget about the wheel pants, they will only make her nose over. :-)