Scott,
I really hope you consider a wired headset mic like my Crown CM311A. It is so fantastic sounding - and I can look at the buttons on the keyboard and at the audience to the side of me while I sing. I can move my head to the music while I sing.
Just as good, I can fit the mic and cable inside my keyboard gig bag, so I only need to carry the keyboard stand and the gig bag (and sometimes a duffle bag with my small monitors) to my gigs. It's so quick and convenient. I can arrive 8 minutes before a gig and be set up on time.
Just consider it Scott, because you wouldn't have to be screwing that clamp on at every gig. I know that a regular mic has one advantage - that you can distance yourself for notes that require higher volume. But the PSR2000 comes with a compressor and that helps a lot.
Whatever you go with, I hope you're happy.
Larry