I believe your question falls into the same file as many many others regarding the Real colours of our subjects. I've reviewed the Osprey books, both the Ace's ones and the Jasta 18 "Elite Units" volume and also taken a quick tour through the D.VII Anthology, and there appears to be no definitive answer. Rather, any comments on wing upper and lower finish state that a mix was likely; some had top and bottom surfaces in red, others had red top surfaces only and some had red only on the upper wing! The photos available don't help much, if at all.
If I've learned anything in many years of WWI Modelling it's that there are few "definites", no one could really call you in error if you went either way! I'd lean very much towards red upper surfaces on both wings and 5 colour lower surface lozenge on both bottom surfaces, but it's your model! Whatever you choose enjoy the Build and I'll enjoy following your progress!
Cheers,
Lance