FFOF is great stuff but in the past always mixed it with either light warrior 50/50 mix or with a 3rd of perlite.
FFOF is dense on its own and does not drain well, try the perlite its cheaper, the light warrior is good but can get expensive. The thing with
FFOF is like you said its rich once you add either of the 2 with it becomes easier to control. I would feed light regardless when using
FFOF.