Chris, I'm more visual than mathematical. I'll leave it to Serge and others to answer your question in detail.
What I will do is answer based on my visual abilities.
Your attached drawing looks pretty darned close to what I came up with, with the exception that the two wings are different in chord, and therefore area. That alone may cause some biasing. If they are also different in span, as well, there may be even more biasing.
I truly do not believe the sharpness of the turn will be that different from a mono wing. with the way I set mine up.
Let me walk you through the way I visualize the wings in flight.
While the wings have positive stagger, they are of the same span and area. The individual wings have a high A.R., about 7.2-1, but with the stagger, they should act together during the turns as if they are a mono wing at about 5-1 A.R., with one major possible difference.
The top wing should be flying in cleaner air during level flight than the lower wing, possibly carrying a significant percentage of the total weight. The lower wing may have some interference from airflow from the forward fuselage, and circular flow from off the prop. Possibly 25%, or slightly more of the lower wing, may be partially blanked by this flow. In level flight, the plane should be stable both upright, and inverted, with possibly a slight percentage better stability when inverted.
I see this because inverted, the top wing, (now the lower), is flying in cleaner air, and there should be slightly less percentage of fuselage/prop blanking by the now top,(lower), wing. This relationship, may alter the force arrangements, making the flying plane seem slightly nose heavy, depending on the planes attitude. I believe that careful design, can help to minimise these effects in level flight.
Now, during the turn, and we're talking about the corners here. It appears to me that during a hard inside turn, the lower wing may see slightly less blanking. The upper wing should be now carrying more of the weight, and making the arrangement appear to be slightly more tail heavy during the turn. More elevator authority may help the turn considerably, but as soon as the design is brought back to level flight, the apparent CG should now appear to move, back to the original force configuration.
Does the same thing happen during the outside turn?
Visualization leads me to believe it does.
So, in my estimation, there are positive expectations that can result from a proper Biplane platform. The problem appears to be figuring out the way to get the LD under control without getting the induced drag too high. I believe that it's possible, and I hope my design is a step in the right direction.
Having said all the above, I realise that since I'm more visual in my application, the proper application of the mathematics may show me that, either I'm correct, totally wrong, or somewhere in between. I trust that people like Serge, and others, will help guide us with either verifying, or pointing out, the errors, or correct assumptions, those of us who are more visual make.
Once the plane is built and flown of course, a lot of questions should be answered.