Sounds like way too much sail for that boat in those conditions. In my limited understanding of sail shape/cut, I understand a genoa is simply a big jib (110 +). In other words a headsail larger than your working jib; typically used in lighter airs. I'm sure others with actual knowledge will chime in here and straighten it out, so to speak
As far as reefing with a roller furling system, it is dependant upon the furling unit being employed some are simply furlers (CDI is a good example as are other "flexible" type furlers), while others are designed for reefing (Harken, Hood are good examples).