Whatever you do, don't use a single pack paint. You'll probably end up regretting it.
I repainted my mast with 2K LPU paint a few years back. It was prepared to the point of all hardware and damaged areas of paint removed. Rather than roll and tip, I just rolled the paint on with a fairly course roller, leaving a correspondingly course orange peel finish. The mast had been repainted before with a mix of 2 pack and single pack touch ups and one "mistake" I made during preparation was to spot sand back to bare metal areas of damaged paint/corrosion. After the initial painting, when the paint was still super glossy these areas showed up as reasonably distinct "divots". Not too worry, as soon as the mast is thrown up it was pretty much unnoticeable. Now after a few years and the gloss has toned down a bit, the mast looks just as good from three paces as If It'd been rolled and tipped or sprayed and no signs of bubbling coming up from the paint. I guess what I'm saying in a long winded way is that the appearance doesn't really matter too much in the long run, just the preparation and paint selection.
Now the boom, on the other hand, is a different kettle of fish because you stare up at it a lot and WILL notice any little imperfections in the coating. I stripped my boom of fittings, sanded every last piece of paint off it and even filled all the little corrosion marks and dings with epoxy filler. I sprayed it with 2k LPU and it came out looking fantastic, and still does to this day.