I recall following your restoration a few years back GoldJazz, nicely done.
The paint that was applied by JBL turned out to be water based, that was confirmed by a swipe of nail polish remover. I lightly sanded all surfaces with 180 grit and had a liter of Sherwin Williams RAL 7038 mixed up.
The top, bottom and side panels were painted with a roller and even after a couple of coats, the original texture was still evident so I left it at that.
The baffles and back panels proved to be more challenging. A brush or roller would not have given the desired effect so they received several coats using the Preval vaporizing system, I have mixed opinions of that sprayer. I went through almost three air canisters just to do those four panels following the instructions to the letter, I believe 2 of the 3 cans weren't holding as much pressure as they were suppose to. At nearly $15 a can, I dont think I`ll be using that system for anything more than touch ups or on very small areas.
On to the crossover