Asonyexec- Yeah, it *is* really hard to do something impressive with silver. Considering the literally hundreds of times I've detailed silver over the last ~30 years, my recent successes were a huge surprise. But then I seldom spent that much time on the job before either (note that it was pretty good when I started too, looked fine under fluorescents), so maybe that's what I needed to do :nixweiss And some silvers are just more impressive than others; my Mazda MPV and the WRX before it simply don't have the potential that the Audis do, or at least I never got 'em to look as good.
DANO- Heh heh, Bill D can speak for me any time, and if I have a different opinion I'll say so any how
What Bill D said about using a Cyclo/PC for the burnishing. Once the finish is basically marring-free I quit using the rotary. Just my (and Bill's) approach though, others are more rotary-centric.
As I got imperfect bonding when applying UPP over 1Z consumer MP, I'd probably go with one of these approaches if using products that're commonly available today:
Use the 1Z consumer MP and put a different LSP on it, one that isn't too finicky about what it's applied over. Not sure what the faves are these days, I'd use (the also discontinued, notice a trend here

) Meguiar's #16.
Or use a different polish and put the UPP over top of that. I let UPP set up for anywhere from 30 minutes to a few hours before I buff it off and I then wait until the next day to add more. Or I just wait until the next wash and refresh it then.
Or you could *try* the MP/UPP combo and see if it works better for you than it did for me. It wasn't *bad* for me, but I had to let the UPP set up for an awfully long time and I thought I could still detect just a little smearing. Seemed much better after the first wash and it sure looked good then. And it was *super* slick (this was on the car during the deer incident, after which I couldn't get tape to stick for the field-expedient repairs until I used some alcohol-based window cleaner on the area in question).