I'm still convinced that a rotary will flatten the surface of the paint better than any orbital can.
With a rotary I can "cross hatch" buff the paint in the direction I want to to more effectively reduce any leftover grain/texture from wetsanding. I normally make two initial passes, both with the contact patch of the pad spinning perpendicular to the sanding pattern. One side of the pad is raised at an angle, all the work is happening on one side of the pad, so all the buffing action happens in one direction. This seems to work well to really cut all texture out.
Any time you're trying to level a surface cross hatch sanding works best. You want to knock down the peaks of the texture without cutting the low areas any deeper. An orbital will let the fibers of the pad reach down into the low spots every time it changes directions- polishing (and slightly lowering) the valleys. You'll have shiny low spots at the bottom of the sanding scratch. Polishing the valley of the sand scratch isn't effective for removing texture- clarity will suffer.
A rotary, with the edge of the pad spinning perpendicular to the sanding scratch pattern will keep the pad from dropping down into the valleys of the sanding scratch. The pad will partly flatten and partly round over the peak of the sanding scratch- the leading edge of the peak being more rounded than the side on the trailing edge of the pad. I make a second pass with the pad spinning 180* from the first pass before the scratch has started to fully gloss up to more evenly level out the peak of the sanding scratch, and go back and forth a couple of times, especially at first- you don't want to round over the peaks unevenly.
Never buff with contact patch spinning inline with the sanding scratches, that will allow the fibers of the pad to drop into the valley of the sanding scratch and polish the peak and the valley more evenly- it'll be glossy but it won't effectively remove the height difference between the peak and valley- the texture won't be flattened and clarity will be poor.