I rig up similar to Piscolli except I use Fireline. Not sure what weight it's been on the reels for many years. I think that it's 4# or 6# diameter. I rig up my leaders ahead of time with BPS Tournament 6# fluoro. Good stuff.
I know that at 1 mph my rig, without splitshot, will run about 15ft. deep. If I need to get deeper or troll faster, I add a splitshot, use heavier jigheads, or zig-zag my troll. The zig-zag makes your bait run at different depths.
My 'line out measurement' is very precise. I cast as far as I can and set the rod in the holder. If it's not too crowded, I'll open the bail after a couple of minutes and let 6-10 more coils off.