I had a FH but I don't use it anymore. There's a guy I with a FH and I occasionally help him.
They are meant to be tight in the FH super for honey to be harvested, otherwise it will be a massive mess. Mind you mine leaked even when harvesting according to instructions.
Best is to place in a standard extractor if they fit.
Not a fan of flowhives myself, and mine is just gathering dust in the shed.