I’d loose the ability to evenly weight Rush with all of the other artists on the empeg (I just couldn’t rate their songs low simply to keep them from dominating),

Why not? A lot of their songs really suck. And this is coming from a Rush fan.

Think of it this way: Rate the Rush tunes against other rush tunes, not against your entire collection. In other words, the 5's would be YYZ, Strangiato, Limelight, Freewill, etc., and then down from there. That way, you get lower overall ratings for the tunes compared to your current collection so it doesn't overpower, but you're still consistent within the Rush collection for when you shuffle just "Rush" by itself.