7.3/4" centre fin side view( it's one of my old windsurfing fins I used on 8' thruster wave sailboard):
These fins have really losened up the board - it has affected the paddling too, it is less stable & when paddling along the flats it turns alot more. I've had a few sessions on this fin set-up now in junky wobbly shoulder-high onshore & it goes well so I'm looking forward to a good big clean swell.
The handle does not balance well - I tend to use it only to get the board onto my shoulder or head for carrying.
To get your wax looking like that: First you carefully cross-hatch using a hard wax on its edge like a crayon - the quality of your lines affects the finish. Aim to get unbroken smooth "crayon" lines. Once you've done the cross-hatching wipe off any excess wax with the flat of your hand. Now wax in the usual way, gently rub the wax on its flat side in small circles. The wax will build on your cross-hatching.