I'm not disagreeing with Walt, here. What I found actually supports what he is saying, and his plane flies, so it can't be wrong. This is an excerpt from an article on fullscale Dr-1 wing failures:

"The Dr-1 had aspect ratios of 6.8, 5.9 and 5.1 for the upper, middle, and lower planes, respectively. The wing section had a maximum lift coefficient of about 1.4. Making estimates of each of the triplane wings (working as independent surfaces) the planes would require 19.2, 20, and 21 degrees respectively to reach the maximum lift coefficient. When working at the same angle of attack (as in the aircraft alignment) The upper wing would produce a lift intensity about 9% greater than the lower wing............."

"The triplane system with its relatively smaller wing gaps and pronounced stagger would almost certainly have a greater value than this. Together with aspect ratio effects it is not unreasonable to suggest that the lift intensity of the upper wing of the Dr-1 approached twice that of the lower wing....."

What it says above is that the fullscale used the same incidence on all three wings, and differential lift from the larger top wing and the dynamics between the three wings meant the top wing would produce almost twice the lift of the bottom wing. My old Great Planes Dr-1 was set up with equal incidence, it flew fine. So.... you could go anywhere between zero incidence and Walt's setup and it would probably fly fine.

The article goes on to say that in the event of the loss of the top wing, it was thoretically possible for the plane to remain airborne on the lower two wings only. Wing area would be about 9.9 square meters, and the plane would have a stall speed of about 64 mph. I'd sure as heck hate having to land that fast in a plane famous for ground looping, but it sure beats the alternative, as happened to Lt.s Gontermann and Pastor, two German pilots who lost top wings on their Dr-1's a day apart. Both died.

You can find this entire article, and many more really interesting ones like it, on "The Aviation History On-line Museum"