To help with top to bottom temps I would try running all the exhaust out of the warmer stack. That brings my top to bottom temps really close. It does create a little hotspot at the bottom right. Once it is up to temp play with the tongue elevation and see what happens. If I need the temp to rise on the right of my cook chamber I lower the left...
Play with it and make exaggerated adjustments so that you can see the changes fast (between adding sticks) and then more and more subtle adjustments until it is dialed in. Good way to get to know your cooker.