I'm pretty sure graham jelley used to fit Bennett st16 which is a 12x16 tab. And that's what's on my 8.1
On my 7.5 I fitted lenco 9x12 edge mount tab, with led tactile switch and power off retractor. Absolute doddle to fit. Because scorpions are warped hulls they plane easy, the tabs aren't needed for that often, unless big heavy diesels loaded up.
I chose the lenco after a walk around scorpion boat yard and a chat with graham who then owned scorpion, he said they didn't need big tabs just to control side to side and windage. I did however bend my lenco in severe weather. I contacted them for warranty and explained what had happened, asked if I could pay extra for the stronger tab which has additional bracing. They refused to take my money and sent me the upgraded tab, free of charge. I didn't even have proof of purchase or have to send anything back. I never broke them.
I recently stripped all the hydraulics out of my Bennett system, I've sold most of it except the pump, but I was amazed how many parts there were to go wrong.