How long of a leader do you use on your lead core line?

Starting from the lure, macks wedding ring green (take the barb off), tipped with worm (sometimes i just put half of a fat one on there, and that usually slows things down but you get a bigger fish, smaller worm, smaller fish usually faster bites), a dot of dick nite trout gel, 50ft of 12lb mono clear, lead core (i think i have 8 colors on the spool) lead 3 colors out i.e. down 10-15ft depending on the trolling speed, then backed with 20ft of 30lb mono around the base of the spool (helps feed the line). I put all that on a penn 109 reel, on a kokanee rod. When you see that pole tap, hold up a bit, if you see it slowly pull down you have your fish. This whole deal when trolling is about 140 ft behind the boat, so mind that, when you hook up, the lure was way back there. If you hook up, circle back and run that same run again, you will likely take another one. Sammaish is an amazing lake to just get out there and enjoy the slow natural fishing, if you wanna just hammer some trout, get some good dinner going, checkout green lake or beaver, they just got a fresh plant of trout, I think over 6k trout each, I hear 1 hour will produce a nice 10 limit right now on both.