I just returned from a second straight weekend with that CLEAVer fellow and my sides are splitting, too.
Matt, is that Maple? The few times I've tried to cleave Maple into planks I've found it doesn't like to cooperate. Hope you have better luck than me!
It's beech. We'll see how it turns out. I've had, I think, 4 good splits so far and 3 that were not as good. Of course, I have nothing to compare it to.