The output of the Dr. Phybes is a low impedance signal provided by the Q5 PNP transistor. From your very thorough description, it is clear that the Dr. Phybes works correctly when sending the output directly into the amp. You say that it also works fine when the Wampler is set to low gain. If you bypass the Wampler and send the Dr. Phybes signal directly into the Moor, do you have a signal loss? If so, that would make me believe that the input impedance of the Moor is too low and is causing the signal to be loaded down.
I suggest you try adding a boost after the Dr.Phybes that has a variable level and a low impedance buffer. If that cures the issue, you may like to try the GPCB STAGE 3 which is a low impedance variable level booster. It is quite transparent and will not colour your tone.