Great points, Bobby Marshall and MC2. Thank you for chiming in. Others have given the same sound (pun intended) advice.
The problem is that I know me. If I have a 12 and I string it as an 8 I'll feel like I'm cheating the bass or like I'm being disingenuous to the instrument (absurd, I know, but I know I'll do that). If I got Carlo Robelli, every time I picked it up to play it I'd be thinking in the back of the mind about the Hamer I really should be playing (and then I'd dump the Robelli after a few months). This knowledge comes from decades of buying basses only to turn around and sell them because I didn't wait until I had just the right one. At this point in my bass playing life I'm really just looking for keepers. And by keepers they have to be basses that don't cause a little voice in my head to say things like, "this isn't really an 8 string bass, it's a 12 that's being deprived of 4 strings" or "sure this bass looks a lot like a Hamer (albeit in silver sparkle), but it's really just an imitation."
I'll also add that I'm new to the Hamerfanclub site, and you people couldn't be nicer. I think as a community we bass players tend to be kind and cooperative people, and this subcommunity is more than living up to that reputation. Thanks for your help and thoughts.