The ground on the sub-T is the bottom connection so don't be concerned with painted ball or not. Definitely recommend the "torpedo" or "rocket/missle" shaped weight for minimizing blowback. The 220 Lb line definitely provides more blowback than the 150Lb. The important part of using it is to be able to located temp and to be able to duplicate the speed of your lure when you catch a fish. Many guys will slow down to land a fish and some even put it in neutral (which I highly advise against). You want to be able to duplicate your lure action.
Browns, Stlhds, Cohos, Atlantics and last year many Lakers were found above the slob Kings. Those guys known for catching the slobs fish the cold water, but also have a lot of other lines out to cover warmer water. Myself having only 3 lines generally put the probe with one line on it in the cold water and two on the other above it. King will look up and it's awful easy to be fishing below a lot of fish on Big-O. Sometimes I'll only have a couple feet difference between rig's but the probe carries a 14 Lb homemade weight but the other is a 10 Lb fish.
Tom B.
(LongLine)