I guess that is what I was inquiring about; if the trim weights effectively move the center of gravity headward. Seems so.
Yes. Simply put, you can try moving a portion of your total ballast forward or rearward until you find the point at which your torso is balanced in horizontal trim. Experimenting like that is the only way to know what works. Keep in mind that if you make other changes, such as a different suit, different tanks, accessories, etc., it may affect your trim. When I wear a 3/2 mm suit (with steel backplate and Al 80 tank), I find myself maintaining horizontal trim and properly weighted for a balanced rig with 2 lbs. in trim pockets on the upper cambands and no lead elsewhere. In that configuration, the 2 lbs. is more for trim than a balanced rig--I'd still be balanced with zero lead. But when I wear a 5/4 mm suit, I find myself maintaining horizontal trim and properly weighted for a balanced rig with 8 lbs. in trim pockets on the lower cambands and no lead elsewhere. Whatever works. You just have to experiment.