How does the scale (size) effect flight characteristics?
 

Title says is all. Althought this is pointed to 3D flying mostly. Let me start with some common sense assumtions, please correct me if I'm wrong.

Smaller lighter planes:

1. Effected more by wind.
2. Less stable (in hovering, torque rolling)? Less mass equals quicker movement.
3. Can fly slower for a given wingloading (something to do with Reynolds I imagine?)

What else?

Where is a good compromise in cost and size?

Most of the guys at my field only have .40 to .90 or 100. One of the bigger planes is a Funtana 40 with a 91. We are wondering how much easier hovering and torque rolling could be with bigger planes.