I can't remember the exact weight of my UCD, but I think it was 7.5 lbs if I remember correctly. I have 5 cell NiMH pack, Aluminum spinner, Cline regulator and Saito 100.

I balance my Dave Brown Vortec aluminum spinner by taking a dremil tool to the inside of the cone and the inside of the plate. Careful not to take out too much in any area. Smooth as silk now. I use the top flight magnetic balancer. It works well.