I'm glad you like the result.
Some tech:
I just got myself a cable (connecting the flash to the body), before that I was controlling (or rather, trying to control) the flash in wireless more and after a long discussion on forums with answers pointing in different directions I had confirmed by Olympus that the super FP mode will not work unless a cable connection is used.
The only way before cable to control the exposure and balance between ambient light and flash was to play with ISO and use manual mode.
With the cable, it is so much easier.
I used a diffuser/softener in between the flash and the fresnel lens. The fresnel lens is 300mm so in theory I would get some 40% (300/480) of the FL50R flash nominal guide number so something like 20. I guess the softener steals 50% or so, so perhaps the real GN is 10. The poor light called for ISO800 (1/160s) and with F/6 I should have been able to shoot at about 13 (8x10/6) meters (in the dark). The distance to subject was maybe 8 meters.
Anyway, just a test. Need more field test to better understand how to fine-tune the flash exposure depending on background.