Burns-bass

My suggestion would be to find a teacher and get some lessons. Most will have a DB you can use, and they can then help you to find an appropriate DB. Don't spend a huge amount of money off he cuff (I say this as someone who did just that), have a chat with some people in the know. Playing upright is a tough old thing to do, and you can get yourself into all sorts of problems if you don't do it properly. If you let us know where you are perhaps we can help! Once you get over the initial horror of learning what is in essence a completely new instrument you'll love it - I bet.