My recommendation would be a short SUP (for looseness in small waves), with a fast (flat) rocker (to take off easily on weak waves), with a wide tail (for power in fat waves) and a wide nose (for stability to compensate the short length).
Simmons, "Tomo", "mini longboard"... all these kind of shapes. Something in the 6'6" / 7'6" and 105 / 115 liters range. Deep Minions, Atlantis Bam Bam, ... Be careful, a "Tomo" shape in 8' will feel a bit cumbersome, you need to drop in length to mitigate the extra wide nose. On these wide tails, your foot is on the kicktail, so a 8' will feel a bit like a barge with the nose so far out in front...
For my 100kg, these are my boards of choice: 6'10" Simmons / 6'8" One (modern fish), both 125 liters. The Simmons for a more stable platform and relaxed ride, the One when I feel more agressive. They are slow to paddle but get into the wave quite easily as the wide tail gets a lot of leverage on the "bump" on the incoming wave. But this means you must say goodbye to just paddle blindly into the wave till you drop, and more place yourself properly and time your paddle to the wave.
More info at:
www.seabreeze.com.au/forums/Stand-Up-Paddle/Review/New-610-Simmons-SUP/For instance, I was the only one out having fun in these conditions with the Simmons:
The wide tail is what gives you the "turbo boost" in fat waves, but unlike prone surfboards the paddle help to control these wide tails