The Z18 should be heavier than the Tracker. I went from a Dual console Stratos with a 150 to a Tracker 175 with a 60 hp on it. I used an Ipilot Terrova BT55 on both boats. I shoot docks most of the time so wind and boat control is noticeable. The biggest difference I see between the heavy Stratos and the Tracker is how bad a wake boat or waves effect it. Some of those wake boat rollers will make you feel like you were launched out of the gate on a bull ride. Wind only moves the tracker around slightly more than the Stratos. If you can face the boat into the wind or current spotlock becomes pretty stable. Spotlock jog is also handy. You can move the boat 5 feet at a time . I have face the front of the boat into the wind. Spot locked it and then shot the docks off the back of the boat.
The love for fishing is one of the best gifts you can pass along