You are right about the concern being tail heavy, for some reason I was thinking nose heavy (senior moment). I was thinking nose heavy because all the "Micro" airplanes are significantly nose heavy. The 1/32 ply doublers up front will help to move the CG forward without the addition of extra weight.
The Dr1 has a 17 5/8" wingspan and 111.6 square inches. The Camel has a 21" span and 138 square inches. They are not going to be racing airplanes.
The CG shown on the plans is at 20% MAC, that should be docile, they would get interesting at 25% MAC.
I also have these two airplanes as 1/24 scale for Cox TD 010.
Pat