Thanks for the feedback...
The strobe is mounted on the left handle of my housing. I find I have a tendency to hold the camera with the shutter release up (right side) because that's how I do it topside. I have a few other shots where I did manage to reverse this and get the strobe on top, but they were largely uninteresting sections of reef. The light is probably actually going left to right a bit, if I remember correctly. I don't think the strobe was parallel to the plane of the sensor but was kicked in a notch or two towards the lense as if I were shooting macro.
As for the diffuser, nope, that's long gone, lost it in Truk I believe, either that or NC.
When I was ordering a couple things before the trip I meant to pick one up. Could have hacked one together obviously, but completely spaced out with trying to get everything else together.
I liked the blue myself. I just wish the top of the reef was lit better, which it might have been had I switched the strobe placement.
Let's see, what else can I post for feedback.... 