If I merge them, I get a file sequence because one of them is animated, and a performance hit from having to load 500mb per frame. While if i can split them up, the animated is very low res and will be a couple megs/frame, while the high res one is not animated, and the 500mb will only be loaded once.
Alternatively, I can bake the animation in the base ocean mesh, and only do procedural for the high res, which is what I'm doing now. Less fancy but it works