I would say bad idea. Flaps will only decrease the overall strength of the wing and shouldn't be needed. They are used to reduce the stalling speed and (depending on deployment angle) add drag to increase the approach angle.

I haven't flown the DP Extra, but everything I've heard is that it's landing characteristics are great. I haven't seen many r/c pilots, doing it, but you can always increase your approach angle by slipping the plane. This is what full-scale aerobatic pilots do.

I have a DP 330L sitting in it's box and I'm planning on starting on it soon. I'm also concerned about the reports of flutter. I've emailed DP himself on the issue and waiting for a response. If I don't hear, I'm going to phone him. His announcement of the new configuration (with dual aileron bays) has only made me more concerned.

Stiffening structures will help, but the main thing is a tight, inflexable control linkage. This means short push-rods and a precision, high-torque servo (100oz.in. minimum). I've got HiTec 5645 (I think that's the right number) 133 oz.in @ 6v for all control surfaces. But, stiffening only pospones the flutter to a higher speed. That's what VNE is for. I believe the real solution is mass balancing the control surface. I haven't read of many that have done this. I would assume, that if the plane is built and flown as designed, that the stiffness in structure and contol attachment (servo, push-rod) should keep flutter at a high enough airspeed to be outside of the normal flight envelope.

The further aft the center of mass in a control surface, the more it's tendency to flutter. Moving it [the center of mass] closer to or at the hinge line will greatly reduce or eliminate the tendency. Stiffness serves to dampen the oscillations.

Anyway, keep reading and educating yourself. That's what I'm doing and hopefully I'll have all the answers before I get started on the plane (well, maybe not ALL the answers...)