Mal,
Some good pictures there and its great to see someone else get into underwater photography
I have been a bit slack of late with putting up some of my images
If I can give you some advice to strobe placement - I am not sure if you have one or two strobes; however,
1. For one strobe - place it directly above the camera housing with roughly a four finger gap. Have the edge of the strobe slightly back from the end of the port and angle it upwards slightly - test and adjust the angle until you are happy with the amount of light hitting the subject. Also you do not want the whole of the strobes beam / light hitting the subject but rather the edge of the beam as this will lesson blowouts, hotspots and backscatter.
2. For two strobes:
a. Macro - generally have the strobes on nice and close to the port and either angled in slightly or outwards slightly* as want the edge of the beams to overlap but not the whole beam.
b. For wide angle - pull the strobes as far away from the camera as possible and then either angled in slightly or outwards slightly*
*Note - depending on the brand of your strobes and whether you are using a diffusers or not depends on whether you need to angle them in or out. I use Sea & Sea YS110As with no diffusers and I need to have them angled in slightly and my mate uses Inon Z240s with diffusers and he has them angled out slightly - so test and adjust to find the best position for your strobes.
Once you have mastered that - then look at using snoots
Here are a couple of photos with me using my setup and trying out my home made fibre optic snoots:
Sorry about the dodgy quality but these were taken by my mate and his new EPM-1 in Olympus housing without strobes.
Here is an image of my setup ; however, I have made some slight modifications - it is an Olympus EM-5 in a Nauticam housing.
Hope this helps.
Karl