I agree on the wetsand, I wouldn't do it DJ.
The SSR's are great, but you do have to work them more. I haven't had luck with the Menzerna. I tried their final polish on a burgandy and it just didn't look right. I ended up re-doing it with SSR1.
How long your pads last will depend on how much product you cake in them and how well you get them clean.
You can't mix them, but Autogeek has six pads for $39.99
http://www.autogeek.net/vcpad.html
The no rinse is interesting being my black does not get to dirty, mostly dust. A little skeptical though.