fertilizer question

what n-p-k ratio should I be using for a plant that just started to flower?
in soil
and another thing is how much of this should i be feeding it with since its in a 5 gallon pot? like maybe 1 gallon of fertilizer(mixed with the water of course)

I Havent done a 5 gal for days.. but i would encourage a transition phase where you give it close to equal NPK.(maybe 1 or 2% more Phos and potash.)but its amount of 'food'(nutrient/water) should be determined by plant size and root area
and if you could.. keep it organic

well heres a picture does this help?
ive been giving it 20-20-20 for its life cycle since week 3

lol... well... if its been accepting 20% macronutrient its life.. im sure its got enough phos and potash but if you could somehow lower the nitrogen (10 or 15) you would see a difference in where it puts its energy (Ex. more flower power and slight less Leaf growth) but be aware that all macronutrients are needed while transitioning into flower..
looks alright so far

You should water once a day(1 gallon should be fine)

You should feed 1-2x a week(1 gallon w/ 1/2 strength nutes, seems like it could handle it otherwise go 1/4 strength)

When in flowering switch to 10-30-20