Chris is absolutely correct. Depending on the size of the guy etc. I would not be afraid to go 20 1/2 x 2 5/8. An outline that a tad wider will have (IMO) better surfability than a more gunny outline, I’m not saying adding to the nose and tail dims, I’m saying add to the curve of the shape. 7’2" in my opinion isn’t exactly going gun, a 7’2" is a pretty good all rounder size. And going a tad thicker a 2 5/8 will not even be noticeable if you do the rail foil right, adding more width and thickness will add a bit more paddle power when you need it.
Also depending on the rocker you choose and how you finish off the tail rocker you can make some dramatic improvements in turning or non turning tweeks…meaning flat board with more cant / toe fins will work in mushier waves, and more rock and less toe / cant for more firing top to bottom waves. More rocker with semi straighter fins you can turn more from the rail line.
Merry Christmas to all here, and thanks for taking the time to write a reply.
On the advice here from resinhead (much appreciated the detail) I think I will take it out to almost 20". Needs the volume but also wants to be able to duckdive it easily, He is what I describe a lanky guy 6’ 6’’ tall also carrying a bit of muscle 90kg.