I used one strobe for some time and had difficulty to avoid strong shadows. The subtility of Rembrandt lighting is that in addition to the direct light on one side, he used reflection of light at the other side. Possibly you could Imitate that with strobe light on one side and natural light on the other. But that would complicate your freediving photography even more.
I use hard type multifocal lenses in a normal mask for many years now. For me it's perfect, but some people can't use these lenses because their eyes are too dry.
Hi, I photograph quite a long time now. For many years with compact cameras, now with an Olympus 5 M3 in a Nauticam house and two Inon 330 II strobes. After a lot of macro hoping to improve my wide angle when waters allow. Dives in the Netherlands and a lot of other places.