Anything you would use in the ocean in that vis will work in freshwater- maybe that means you can keep using the gun you already have?
I guess I would prefer a Eurogun with a single wrap and no more than two bands- one being preferred for quicker reloading. I really liked my R.A. for the size of shaft and the quick reloading that it offered. I also found it to be pretty accurate due to the rail. I ended up selling it because the 75Cm, that I owned, was just too muzzle heavy and became tiring after a few hours in the water. It was also harder to shoot at fish sneaking up behind my shoulder in the weeds- which my mid-handle does extremely well at.
This last weekend I had a chance to shoot a 90Cm OMER Cayman HF that belonged to ILDiver. It has been the ONLY rear handle gun that I have used that's neutral in freshwater. I don't know it if it's the gun, or just the length of the barrel, but it was a pleasure to shoot- and with your vis it wouldn't be too long.
We shoot 40 pound carp with just about anything made and they will all work-your bass shouldn't be any bigger than that. The big thing is how big a hole you want to put in the side of them? I like my pneumo for carp because it's the fastest, easiest to aim gun I've owned. I understand that they make a Mamba it for it that would increase my distance, but that's not needed for my local conditions. the Mamba kit would make it much easier to load than the standard Cyrano.
When it comes to panfish I don't want to ruin the meat and the fish aren't that big- under 2 pounds. That means a thin Euro shaft works out better.
I had great luck with the R.A. and the OMER's have worked for a number of people I know. I have to admit to being less than impressed with the Hammer Heads, but that could just be the problems that Whopperhead has had with his- anyone can have an off product in a large production run and they did offer to fix it for him.
The diver I met was using an OMER of some sort that was at least 110cm- can't remember for sure, but it was huge. I had a long wooden gun originally, but it was too long for the vis and I always ended up shooting it from my hip. I still managed to get more than a few fish with it, but it wasn't much fun for diving around here- would have been great for where you are. I've attached some pictures of the last time I used it so you can see why it didn't work out so well.
I also attached a shot of my catch from yesterday- which I did with my Hawaiian sling. Last shot is one from ice diving- which isn't as bad as it sounds IF you have the right wetsuit.
Sorry for the rambling post, but anything you would use in the ocean with that kind of vis would really work just as well for you there- tuna floats and 6 band guns aside.
Jon
