Thanks guys. I think I do need a "blacker" fabric like velvet. Somethig with a lot of surface area that will absorb more light. I was just using a regular black woven that was probably reflecting too much light.
Since I'm using a RB67, I do have the ability to sync with a flash at any speed. I dont really have flash that I can control that well though, which is why I'm using continuous lights. I'll try to see if I can get more control of the light as well.