I'm partially in the same battle. I attempted some swirl removal by hand with Meguiars Scratch X. My success was small. Maybe somewhat improved, but not a lot with the work that I put into it. I think I found my solution, though. About a month ago, I used my mom's Makita finishing sander on my passenger door with a pad I made for it. I ran it with scratchx over it a few times and a month later, it is still mostly swirl free. I do see some little "orbital" marks where I must have picked up a grain of sand or something. Much better than before, though. I think my attempts at swirl removal by hand seemed useless, but the swirls were from a rotary buffer. :shocked Maybe you can get regular swirls out by hand. The only thing you can do is try. Start in a small area and do some work. When you're spent, give it a rest.
Regarding your metallic paint, it won't make swirl removal any harder than straight black paint. It might even be easier to be satisfied because some of the metallic flecks might give the illusion that there are less swirls.

One thing that I can almost guarentee you is that you have clearcoated paint. just FYI.
One step that you might want to take not necessarily to remove your swirls, but to make your paint nicer to work with is claying it. There are "poly clays" I believe which are plasticy type clays which have some abrasives imbedded in it. What those do is "shave" off any contaminance that are stuck to the paint. It won't, however, shave off much of your paint, just the stuff that is sticking up (contaminance). I hope I got that explaination correct...
Back to your swirl removal...I was happy with how my mom's makita sander worked on my paint. The only downfall I found was that it has a square backing plate. I imagine if you found one with a round backing plate that you could addapt most any coresponding 5 or 6 inch pads. PCs are rated up to 6000 orbits per minute as you might know. The finishing sander that I used was way up there (something like 12-16k) and was only one speed. I presume that the finishing orbits are smaller than with something like a PC, but never the less, it proved effective for me. There are also cheaper rotaries available. A Chicago Tool rotary can be had from Harbor Freight for $40 right now, but usually $50. As with anything, you would probably want more pads. Not that I am giving you any recomendations, just options.
Sorry I can't help you more in the area of how to rub your paint and what to rub it with to make your swirls disappear. Somebody else will hopefully come along with that.
Kev
