Flash has never been my cup of tea with film cameras. I hate all the wires, bulk, batteries and the unnatural look that happens when I use the things. I only use available light.
I've used my Rolleiflex successfully with available light, it seems to suit as well as my Leica M4-P. To fill in dark areas I'll have someone hold a white piece of paper just out of the frame to fill
in the dark areas.