What is your low powered tube amp? The reason I ask is I have a pair of OBaby's (no I dont live in the bay area, sorry), own/have owned O93's and O96's. While the traits are similar up and down the line, the OBaby's are 90db/8ohm speakers and the O93/O96 are 10 ohm with their efficiency number embedded in the model name.
Please do not think the OBaby is just a smaller O96...the Obaby is a darn nice speaker but I wouldn't consider a "low powered tube amp" and the OBaby's. I run my pair in my office with a 15wpc tube integrated for background music while I work. They benefit from some power and my office system would never cut it as my main system if that makes any sense.