Sasha; What are all of the settings you are using on the camera?
In general, I usually add a +.3ev to the TTL camera flash compensation as it moves the strobe to a more useful range.
Basically I would move out of all the auto settings and or use something like aperture or shutter priority. Camera varibles can be hard to figure out. Shooting in manual is best so you can work both aperture and shutter.
Be sure auto ISO is off. ISO should be set as low as possible; 100-200 for macro, maybe 400-800 for W/A
White balance on auto.
Try it out with moderate camerasettings ISO 100-200,1/125th, f/8.
Use auto focus, single point, spot. If you have a manual focus gear for macro some find it easier. I usually just rock the focus point to where I want it once locked
You cannot sync the shutter faster than 250-320/sec. it physically doesn't work on the camera. You have to set that in the e1 flash sync speed to 1/320. I've found shutter speeds of 1/200-1/250th to be about it in some cases with TTL. Shooting manual sunballs at 1/320 is no problem.
If you're using TTL on the strobes, then the camera menu item e3 Flash control needs to be set to TTL, if you're using manual on the strobes, then set to manual on the camera - low power like 1/125 speeds up camera recycle.
These are a place to start. As you get into it, play with one setting at a time to see what it does.
I've shot the Nikon 17-35 with the Zen 170 on my D800 quite a bit. Corners aren't great, so you need to stop down and shoot around the problem a bit - move the corners into the blue or black, maybe crop a bit. But I find overall that it shoots fine, and most of the time I'm using that lens for bigger animals out in the blue anyway. The turtle below had pretty soft corners, but with such a large file as you have on these full-frame cameras a lttle cropping doesn't hurt much.
I've published a Port Configuration Guide on our blog that has all of the various possible combinations for Nauticam and Olympus housings with Zen, Nauticam and Olympus ports, extensions and gears.
There's a lot of different configurations. Right now, there's not a one size-fits-all like with DSLRs. The optics on m4/3rds lenses and the large physical size of the Olys make it hard. But I think given some time the manufacturers will do the best they can to work towards that goal.
Having shot the 8mm with the small Oly dome, I'd really like to try in with a larger 170mm dome and see how much less edge distortion it has.