Surfing Waves

I tried to search it up but the words i used kept being too general.
What fins do you guys recomend on my board?
I have an epoxy 5'11'' which is said to be good to waist to overhead waves, but ill be in smaller surf. I have the pc-5s on it and it seems alright, but then i dont have much experience with other fins.
Then I have a 6'4'' which i have in generic fins. The tail is a narrow squash, so I am thinking the board will be good with bigger waves like chest to overhead. The board is also obviously less responsive than my 5'11'' but is a lot faster. When I put in the PC-5s its reallly really fast.

So her is my question. I only have one set of pc-5s. I am wondering where is should stick that one in, and what new fin set i should get. Fcs that is... I was thinking just leave the pc-5s on the 5'11'' and put in some stiff carbon fins for the 6'4''?

i dont use fcs all my boardrs are futures - but when i did use fcs i liked the kelly slater ones a lot cant remember what they called

the k2.1s?

The PC5's are good for both boards, I have them on one of my boards. My 6'2" shortie has the Rusty Carbon Lites, I like them stiffer to bite into the wave more and turn harder. The k2.1 are also a great set for the small bard, the center fin is smaller which makes it more responsive.

For big waves on my 6'5" I use GMB's, which are my favorite all purpose big wave fins, second choice for big waves are OCCY. Both are slightly bigger than M5 fins but not have as much toe in, so you get more glide and more hold at the expense of turning a little less sharp, but for big waves I'm not looking to cut hard.