I was always told to use slam immediately following a white hit. So I setup some swing timers and started whacking away. Hitting slam as soon as my white numbers floated up from the mob. This is bad. My swing timer was completing and almost a FULL SECOND later, the white numbers would dance up from the mob. As I gained a little more experience, I noticed that as soon as my swing time completed, the mob would lose health, a second later the white damage floated up and finally I'd hit slam. I was losing massive amounts of DPS using slam this way. When soloing, watch your targets health bar. Don't wait for the white hit numbers to show up. They show up extremely late. Go by the health bar. As soon as you see the chunk of health evaporate from your target, cast slam. Most of the time I don't even see the white hit damage numbers at all. Once I see the mobs health go down from a normal swing, that's my queue to hit slam.
I don't have logs or hard numbers, but I'm level 38. I was keeping barely ahead of a 42 rogue in scarlet armory last night. He was flipping me shit about not spamming cleave too. I think cleave is too expensive but that's another discussion. Just grab a swing timer. There's a few of them around. If I were home I'd post mine up. But tldr of my post it, don't wait for white damage numbers to pop. Watch the mobs actual health bar and pop slam when it gets a chunk taken out due to your white hit.