I just had a C extension put on my bass with only an E stop for now. Generally I'm finding that shifting from half position to the extension Eb and D is a little tricky, but do-able. However the Db is tough to reach. Also its very easy to get hung up on the tuners. It should also be noted that I prefer to stand while playing, but sitting definitely makes getting the low extended notes much easier. What are your preferences? Any tips on how to navigate a fingered C extension would be helpful. ....or maybe its just a matter of getting out the Flesch book and sawing away until I figure out my own system.