We have a TG-4 (similar enough to TG-5), and use the following settings:
Macro:
- Auto-WB -- you're using a strobe, so no need to use the underwater white balance
- Shoot in Raw + JPEG. If your strobe is too close/too far, the RAW will give you more latitude to fix the shot
- Flash forced on, because you are using the strobe
- Underwater mode + microscope mode for macro. Wow can this camera focus close
- Strobe set to TTL (actually I think YS-03 doesn't have any other option -- I forget because we have a YS-01 and YS-03)
- Center focus if your shooting macro
We have not used the diopter with the TG-4. I see no need with the microscope mode. We also have a Oly OMD-M1 and that camera DOES need the diopter to equal the shots taken with the TG-4. I also recall that I limited the min shutter and max ISO, but don't remember what settings specifically.
Wide:
- Auto-WB or UW-1 WB, depending on if you use the Strobe or not
- Shoot raw + JPEG
- Flash on/off, depending on whether you're close-focus/wide angle, or just wide angle. Personally I've found wide angle with no flash/strobe at depth results in crummy pictures. Focus isn't great, color range isn't great. Basically a good 'tourist' shot, but nothing worth printing
- Center focus or at least adjust your focus/metering to the main subject
We don't have a wide wet lens for the TG-4 so can't comment on that.
Good luck. As you've probably read elsewhere, this is a very capable rig, and a joy for macro like nudibranchs. The microscope mode really shortens your working distance, but it is great for slow moving small things. The focus light is a good idea to speed up the focus.