The hardest part of moving from bass guitar to upright is learningto listen to what you're actually playing, not what you think you're playing. So F (root), C (fifth) on a guitar is straight forward, first and third fingers and hit behind the fret. On an upright its first and fourth and hitting on the note, not somewhere behind it. As you shift hand position up the neck you don't have these really useful frets to make it easy, you have to be accurate and the only way to be accurate is to listen to the note and develop your ear so you can adjust.

It's great fun, I'm making the conversion, but it's not that easy.

Steve

PS I'm a great fan of open strings, especially when starting out, because you know they're in tune and so give you reference points for the other notes.