Hi Badabong
Welcome to AFN buddy!
Why not pop up a hello over at introductions for a nice warm welcome from our members!
I don't really bog myself down too much with ratios and just go for nutrients that i have seen others succeed with, but i'll have a stab at answering your question
do you think that the ratio between Nitrogen and Phosphorus, Potassium is that important.
Yes.
You will want a higher ratio of nitrogen for the Veg process (pre flowering), and a higher Phosphorus and Potassium ratio during the flowering phase.
If it's a first grow, i'd recommend keeping it simple and seeing what results you can get with the minimum of nute line up. That way if something goes wrong, you're not guessing at one of the many things you've popped into your feed
It also gives you something to compare against when you start trying to push your skills with bloom boosters (pk13/14 etc)and all the other things that you can chuck at a plant.
Start your seedlings off nute free so you dont burn them. About 2-3 weeks in, introduce a small amount (1/4 of the manufacturers guide) and keep them nice and green and healthy.
So in answer to your question (finally)
PK 13/14 necessary?
nah, not really - but it might make your buds bigger and heavier if you use it in the right amounts at the right time
Hope (some) of this helped a little
All the best
Blue ^_^
:High 5: