Hi,
Yes the particular filler that I use will polish extremely well. I call it my "Piece of glass in a bottle".
For sanding curved areas (including edges), I use a rubber rectangle on which I wrap my sanding paper. Excelent results this way, if you remember to "cross sanding" to avoid bumps and recesses in the surface finish. Modify rubber thickness to your likings.
For guide coat I simply use your basic mat black spray can, I spray it more like a mist, not a real coat if you see what I mean. Yes, it's a spray can stuff, but since you're supposed to make it all go during sanding process, its ok. I use mat black cos gloss black takes too long to dry.
I start sanding the guide coated filler with 600 grit wet paper. Then I go all the way to 2500 grit before polishing. Always wet sanding, and I change the water in my cup after every stage, to avoid recreating scratches from bigger grit contamination.
For polishing I use a 75mm diameter polisher machine (mine is air pressure driven) with foam polishing pads from 3M, and 3M polishing compound. I go thru the 3 stages (coarse, fine and ultrafine). Some will say its too much, and I might agree with them. However, it's how I feel it is right to do, so I do it like that
Whatever polishing machine you want to use, please be aware than you should not use a machine that rotates in excess of 2000 rpm. My machine spins at 1000 rpm maximum, for example, and I never use it at full speed. Some would use a grinder or modify a tool they have, to save money, and they would prolly end burning their part or distort surface finish cos of excess heat. Be careful too if you are gonna use foam polishing pads, they tend to heat more than wool pads. However, if you keep on moving the pad on the whole part there is no problem. Plus I find them to create less swearls than wool.
Once again, this is not the only way, other people would have other methods and products that work as well.
Hope it helps.
A $1000 electronic device will always protect a 10 cents fuse