I can't advise on water born as we don't have to use it. We use both 22 line and 55-line base coat with clear. We did the roadster with base/clear, then did another car with single stage 22-line. I think the single stage is easier to get flat when you are wet sanding and buffing. If you have to make a repair later this is easier to do with base/clear, but I'm leaning toward doing all the non-metalic jobs with 22-line.
But maybe you have to use water base?