I've just added the Simandl Etudes to my practice - somehow I never got to them earlier (I've been playing for 25+ years, I'm sort of an advanced amateur). My plan with them has been to read 1 etude per day and to try and play it as well and as musically as possible. I'm not worrying too much about fingering or even playing perfectly - once I get through the book, I'm going to start right back through and try to do better the second time.
Watching the OP's video, I think he's doing a nice job overall. I can definitely see some stress creeping in. Here are a few suggestions:
Check out Dennis Whittaker's
video on centering, and try to find places in the piece where you can take those breaths and relax your body and your mind.
The bass moving around sympathetically as you play, like with shifts, string crossings and bow changes. Moving isn't a problem per se, but I'm getting the sense that you're not completely comfortable with your posture and setup. You may want to try making some small adjustments and see if you can find a position where the bass is braced by your body but you can still reach around for things. I'd suggest taking a small step back and having the instrument slightly less vertical. You may need to adjust the endpin.
As other people have mentioned, you probably don't need to avoid all open strings, but approach them musically. Also, for your first pass, I would definitely emphasize other aspects of the etude than that.
For tuning, I play with a drone on the dominant (V) or sometimes the tonic (I). It's okay to check some notes with a tuner, but try to rely on your ear first and foremost.
Great work. I think you have a lot of nice stuff in there.