Considering a larger wave

Now it's my turn.
I'm 67, 5'7" and 135 pounds. My 90 liter longboard has extra nose rocker and a thruster with 6 inch fins. My popup is great for the first hour of a session and then gradually becomes a "slop up." So far the biggest wave I've ridden is about 6 feet. At that size I notice that despite my efforts to weight the tail my fins start to lose their grip with the water and I skip around a bit. I love to glide and don't do maneuvers except for the occasional foam climb.
I planning trips to Black Point in Sonoma County for waves like this....
What do you advise?

I'm 67, 5'7" and 135 pounds. My 90 liter longboard has extra nose rocker and a thruster with 6 inch fins. My popup is great for the first hour of a session and then gradually becomes a "slop up." So far the biggest wave I've ridden is about 6 feet. At that size I notice that despite my efforts to weight the tail my fins start to lose their grip with the water and I skip around a bit. I love to glide and don't do maneuvers except for the occasional foam climb.
I planning trips to Black Point in Sonoma County for waves like this....
What do you advise?