I posted some links in another thread that had a couple of $200 strobes, an Epoque & a Sunpak.
I got a reply from an Epoque dealer in Australia who explained that it simply ignores the digital cam's pre-flash and uses whatever manual setting you select. The manual setting is adjustable between Guide Numbers 3-15, but I don't know how many settings there are. It has a 80x100 degree flash angle, which you could probably increase with a diffuser.
My 1st UW camera was an Epoque ET-110+. The picture quality was a step above the Bonicas & Sea Snappers etc., but the hardware was cheap. After about a year and a half, the rewind motor started flaking out then the film spool cracked.
I haven't heard a word from Sunpak.