[Fafnir_6]

While the Ju390A-1 is interesting, I would vote for doing the 4-engined Ju290A-5 first, since many more of these were built and they could be used for Maritime patrol missions (e.g. Norway) and for the Stalingrad airlift (Ju290A-1s, I believe). Once the Ju290A is complete, making a Ju390 would involve stretching the airframe and adding the two extra engines.

Cheers,

Fafnir_6