Hi Maxum;
Yes you are correct that very early in the season they are at the top but not for long. A couple weeks later on and I have found them again back right on the bottom.
60' of depth would require 10 colors of line. depending on how fast you troll (I troll around 2 mph) as lead line usually sinks around 6' +or - per color. I use a large Penn level wind reel that has 20 colors of line on it. 10 colors is sufficient however with plenty of backing on it.
There are some drawbacks fishing with lead. First off though it produces lots of fish, it's really not too much fun yanking up a small or average laker that feels like a water logged boot because of the weight of the line and a saltwater sized reel. It certainly not like the salmon that hits your gray ghost on a fly rod!!
The other thing is if you are a catch and release fisherman (I am) dragging up a laker that was hooked on 10 colors of line is completely exhausted and has less of a chance surviving when released. This is where proper handling / netting really offsets this issue. I am seriously thinking of going completely barbless and single hook only this year and see how it works out. I guess every little bit helps...
Dan