I agree with the above and would suggest that since the real airplane was basically a slow flier that scaled areas would be OK. If you can find the full scale CG location I would feel comfortable in using it.

In doing stabililty calculations I think you would consider it to be a wing with 3 times the lift of a regular wing with the span and chord of one wing. The existing horizontal tail is about 3 times the area needed to stabilize a single wing especially with that moment arm. You have 3 verticals of a size that would be adequate for one wing, fuselage and small horizontal.

It looks like the original designers just multilpied everything by three!.

That rigging job would take the patience of Job! The drag was probably measured in tons.