Standard Orange walleye boards work fine for all lengths of lead and copper. I use 300 feet of copper and they work fine. Move the weight forward to the #2 position. Keep all your boards the same. Buy them at Northwoods (cheapest). Use a rubber band at the back, slip knotted to the line and then fed into the pin ewith the backing line to keep it from sliding down toward the fish if ithe board releases. I tighten up the the board's release to the max tightness and use braid (40-50#) as backing to give you a lot of line (smaller diameter than monofilament) after the core just in case you hook up a big fish that takes a lot of line. If you encounter a really rough day, just route the line behind the board's release so that it is impossible to release. If your reel doesn't come with a peg on the spool, put about 50 feet of monofilament on it first before the braid. Braid is so slick, it can spin on the spool. Monofilament will keep that from happening. 95% of my knots are palomar. It's the best as proven by knot wars on YouTube. As for tying line to the leadcore, I remove 2 inches of lead from the end. I then put a loose, simple knot in the leadcore. I move this loose knot up about 3-4" from the end. I then take the monofilament or braid end and insert it into the leadcore without the lead about 1.5". I use a sewing needle to help with the braided line. Use a good pair of nail clippers to cut the end of the monofilament before inserting. This makes insertion a lot easier. Once you have the 2 together, (2" of braided should be sticking out the side of the core casing, move the loose knot over to tighten on both lines. Wet and pull hard. I add a double knot on the end of the braided and work it back inside the core casing. This keeps it from slipping through knot. When reeling in your board, point your rod tip down, close to the water, this makes the board skip over water toward you and not dive under. One more hint/trick. To maximize backing, load up a spare identical reel backwards (leader 50 feet, lead core and then the backing). Fill the reel as much as it can handle and then reel it onto the reel that you want it on. Since a 20, 30 or 40 pound salmon will test everything in that system, you don't want to get spooled and loose a big fish just because you don't have enough line on the reel.
Good luck and tight lines.
Joe