6'4 or 6'6

Hi first of all thank you for taking the time to read this and to reply.

I'm 28 years old started surfing three years ago but really i have been constant since last summer.
I recently started to go sideways and move up and down on the wave.(6 waves total per day and 2 or three all the way from the line up o the rocks). My wave count has increased from 2 to 6 and now i want to learn on a smaller board because the one I have now is 7'1 x 21 1/2 x 2 3/4.

I have gotten tired to get to the line up, but then I rest and give it my hardest paddle to catch waves and then i get a little tired to get back to same point and have to rest, but surprisingly I didnt get tired on my last session.( maybe cause my ribs hurt only on one spot).

I regularly dont say this, but it may help for the purpose of the discussion. I've had an aneurism when I was 16 and I get tremours on my right arm and right leg, sometimes it does affect my surfing, and deffinetly when I paddle my left arm goes through the water harder than my right.

In any case, I talked to a shaper that my cousin has gotten boards from, and he recommended 6'4 x 20 22/25(.88) x 2 22/25(.88) comming out to 37 liters.

the wave height can be from 4ft to 7ft.

Told him everything that I have said here, and will spend in summer 3 days during the week, maybe a little more(right now im up to two days a week because of work and university). I will beat y way through getting used to that board if I go through with it.

first, what are your thoughts of me getting the board, is round pin, wider nose and other things to help my paddle according to the shaper.

second what do you guys think about a 6'6.

again thank you for taking the time to read and help me out.