Sorry, but the Oboe is really not going to help you learn the Bass Clarinet. The oboe's fingerings are more similar to the Flute first off. Secondly, as you stated, the embrochure is very different. I play the Clarinet (B-flat), and have been playing for six years. Even then I have the most terrible time trying to play anything with the register key on the Bass Clarinet. I can still do just about anything possible in the "Belting" range of the instrument, though. I highly recommend that you take some time to try the B-flat Soprano Clarinet before playing the bass, though I do not know if it will be easier or not.