Quiksilver,
There’s a book out called Precision Trolling. The latest is 6th addition I believe that came out last spring 2001. You should be able to find one at Cabelas, Gander Mt., Fleet farm, or others.
As for those clip on line counters–I have a couple of them on the bottom of some lakes and they are worthless. Buy the Daiwa LCW line counter reel (walleye version-check the product review on this board) and save yourself the headache by doing it right from the start. That’s what I did. Brian/TGIF