I usually find that when the rigging bite has died and the spinner bite is dwindling, the trolling bite is rolling good.
Try not to get hung up on setting your lure to that “perfect” depth meaning that having to hug the bottom or needing to let out more line because you feel your lure is too far off the bottom. These fish will chase a lure from a long distance. Throw in “S” curves or stall by shifting into neutral on occasion to entice a strike.
Once the trolling bite is going later in the year, the fish are fat and sassy and have seen the spinners and rigs for 6 plus weeks. They are not necessarily hungry, but more often angry at the faster moveing cranks and will just pound them.
My go to is a blue SR5 and I also like the #4 and #5 Hornets. I run lead core; use the Bible for the dive curve for the length of the leader you using and add five feet of depth for every color let out at 2 MPH trolling speed.
Start perfecting your technique this weekend so you are set to go in late June, July and on to late summer.