Here's my bit.
Copper is a pain in the ass, no way around it. You mentioned buying two. I would never under any circumstance try running two copper rigs. We have it because when the kings go deep, it usually becomes our heavy hitter, and we
need meat in the cooler. Botton line we run it only because when the bite gets pokey, it can be the difference between a five fish trip and a ten fish trip. If I was fishing for myself, and meat wasn't and issue, no way i'd mess with it. We do it out of need, not because we like to. If the fish are coming fast enough (if we can count on 4-5 bites an hour), the copper stays on the rack. When it's going down, copper is too much to deal with, and you will spend more time dicknig with it than focusing on your rigs that are getting bites.
When we do run it, (kings are biting 70 and deeper) we run our four riggers, two mag dipys with the big dive rings (depending on current), four big birds with 12 oz balls usually out 200ft or better behind the board, and the copper out the chute. Our copper is #45, and I think we start with 400ft on a spool, but that ends up getting trimmed down as you get tangles. We have a mega-ass load of #80 power pro backing on ours. I'll let all the copper out and stick the rod in the holder, when I see that the knot is touching the water (all the copper is in the drink) I'll start letting out line into the backing, counting the levelwind passes on a Shimano tekota 800 (no counter, not needed). Anywhere between 10 and 30 passes, whatever it takes to get bites (are you starting to see why I don't like this?).
It makes for some truly savage strikes, though. Those kings really torque that bitch over good with that copper line.
Sure wakes everyone up.
Closing remarks.1) Hookup ratio is poor. If we hook 50 percent of our strikes on copper, we are doing good. I've dicked around with every drag setting, some days they get the hooks, some days they don't. Loose drag is better than tight drag. Like I said, they torque it over good when they hit, if the drag is too tight, you lose them everytime. Tighten drag as needed while fighting the fish.
2)Two coppers is out of the question. Save the money and the headache, just get one, if that.
3) Do not use it in less that 100 FOW. And only when you can't get a bite above 70 feet.
4) Once you put that bitch out, you're married to it. Have rod holders available to move it around as fish come to the boat. Always being watching it, copper tangles are the worst tangles.
5) No more driving like a tin boater. Big, gradual turns, if you think you're turning too sharp, you are.*
6)Find a diagram that shows how to tie that mother-lovin knot, and keep it on board. You're going to need it.* (the knot joining copper to braid)
7) Ten feet of mono leading from the copper to your terminal tackle is plenty.
8) Put it out last, setting boards and jet divers with it out is high science. Try avoiding it at all costs.*
9) Let it out slow, or she's going to back up on the reel. If you are setting the copper, that's all you are doing.*
*Just let Jr. do it.