Ham,
I play upright with the following setting:
Erhlund Pickup, Rh450, to either 212 or 112, or both. To be fair, this setup is pretty new to me (upright and erhlund, have had the TC stuff over a year) and I have only done 1 upright gig with it. My thought were that perhaps the RS210 will work better with the upright as I had to spend a lot of time dialing out the lows and lower midrange. The TC amps have a built in eq curve that is meant to compliment a passive Fender bass (IMHO, your active Alembics sound great too, I know) and they are midrange heavy. Most DB piezo pickups are ALSO midrange heavy, so you have to dial a lot of mids out. I felt the tone I got was pretty good overall. Alot of this is due to the Ehrlund pickup which is simply amazing.
If you lurk on the DB forums, most guys over there seem to like amps with as little coloring as possible, like the Acoustic Image stuff, or even a high quality powered PA speaker like QSC. The same goes for acoustic guitar where you want to hear the natural tone of the instrument, and not the amp as much.
While I LOVE the RH450 for electric bass, for upright, it takes a fair amount of fiddling to dial in a great tone. What really helped me on this gig was my Radial Bassbone, which has a very nice EQ in it. I was able to dial out still more bass and mids with the radial which helped me find a very workable tone.
Since I can't afford to have TWO high end amps, will just have to make the rh450 (or 750 soon!) work for me. I know it can get there, as Esperanza Spalding uses one, but I need to fiddle around with it to find the right setting.
One huge plus with the TC stuff is that I was doubling on this gig (hence the bassbone) and having the eq presets was a lifesave. I had two radically different eq setting for the upright and electric, and it was pretty nice to be able to hit a button to go back and forth from these settings. It would have been a nightmare trying to re-eq between each song. In that regard, the RH series is a GREAT doubling amp, as you can dial in your tone during soundcheck for each bass, save the EQ on your amp, and use the footpedal to go back and forth when you switch from upright to electric.
I plan to upgrade to the 750 as soon as I can sell my 450. Ideally I would keep the 450 as a backup, but you can't have everything. I am hoping the added highs of the 750 will be useful on the upright, and that adding a 210 will act as a natural HPF to take out some of the boom I get with the 212.