I've never used FF, but they sell a "trio" of bottles (big bud, grow big, and tiger bloom). It's common to use those with that soil. I've read that HF comes with enough nutrients for 4 weeks. You'd probably start 1/4-strengthen week 3, then 1/2 strength week 4, and full strength after that. (Whatever full strength is. I don't know what is considered full. Absent someone telling you what that is, if you followed FF's schedule for the "trio," you would want to consider half that being "full strength.").
You don't need themed nutrient products, with schedules. You could use any fertilizer that has a reasonable ratio (like 16-16-16, balanced 1-1-1 ratio). You don't need boost P in flower. I haven't noticed much difference either way. The brand doesn't matter much. I've grown two plants using MiracleGro fertilizer (Tomato, and right now growing a plant with All-Purpose. I'll probably switch to Tomato in mid flower. It's a 1-1-1.2 ratio. Whereas, All-Purpose is 3-1-2 ratio. Much higher N for veg. Maybe too much for flower.
Anyway, my point is: the safe bet is probably using the "Trio." Follow the crowd. But, someday you should try a simpler routine and see how it compares. Put together your own "schedule" using ordinary products (found at the hardware store). Fish emulsion, kelp, guano. All you need is a balanced base nutrient (like MiracleGro tomato), and supplement with fish emulsion for higher N in veg (and guano for higher P in flower, if it matters). Kelp at end of flower as a bud hardner.
I'm just saying, if you go with the familiar franchised feeding program (I probably would, in your shoes), don't forget that you can do your own thing. It doesn't require "formulas" like that. You can put your own stuff together, cheaper, be more aware of the NPK ratio you're creating.