I have tested the greenbacks with vintage 30's(v30's bot-gb's top) and I didn't like them at all...too many highs and not as mellow as my greenbacks...
I guess the retro is a kind of v30 so I wouldn't try one again...
Sure, you can go with Green Berets for an all classic Marshall tone. Actually, though, given what you said about "too many highs and not as mellow...", I'd recommend a pair of ET65's or Invaders to go with the GB's ... they are both voiced along the lines of the classic pre-Rola GB tone, but the ET65 is a good bit warmer, and the invader is just a TOUCH so!
Also, when searching classic 80's/90's hard rock tone, check out this Q&A:
The WGS are more bassy and have more low mids than the celestions.
Celestions are cleaner and more defined in the highs,
The WGS would be awesome in a 2x12 or 1x12 due to the "extra" bass.
I tried to X them I didn't like it so much.
I placed the WGS in the bottom and the celestions at the top.
Sounds very very good!! the defined highs are there and I can hear them(use an angle cab) and the low mid punch comes from the wgs placed at the bottom.
If I wanna change something(not now) do you think the ET65 could give me the detailed highes of the greenback and the bottom of the green beret?