My step ups have been developed over a number of years of research with the team and myself surfing in Hawaii, Mexico and Indonesia. The transition from your short board to your step up should be an easy one. Taking into account more power of the bigger waves and the higher speeds you travel; the concaves have been toned down and the tail foils thinned out a tad.
The step up range has been proportionately based from the performance board range, this helps create a special friend that you know and can trust. When the waves are a scary 8 to 10 foot, it can be the only friend you’ll have. The board should hold in and change direction with a sense of security under your feet, no matter how fast you’re going.
A pin or rounded pin-tail is generally the go for maximum hold. I have also been playing around with mini swallows which have been feeling good. Available 5'10” up to 8’0”(Bigger if you are a major charger or you want to talk it up to your mates).