RE: Single Wing To Biplane
The nice thing about our hobby is that we can afford to experiment. It's relatively inexpensive to make modifications to a plane just to try them out, and you're not risking lives (i.e. passengers) based on TLAR engineering (That Looks About Right).
It sure sounds like you've got biplane on the brain. Why not give it a try? For starters, you could simply add a second wing, identical to the first.