OK, lets think this through...I agree with the previous posts, but here's some additional tips.

The gap is just fine (1/16" of an inch? What’s wrong with that on a trainer?!), as for the rudder and nose wheel, fly it with some counter rudder on take off, and when in the air trim so it tracks straight.

1) When you land, go to the/a parking lot/basement/flat smooth area, and push/roll that sucker. Watch it for any side movement and adjust the nose wheel mech's, not the trim or the rudder. Make sure you don't yank to offset the rudder servo, just use a light touch and small adjustments. Roll it on the pavement again, and watch how she tracks. Adjust accordingly. You should normally look for a 15’ roll. A few degrees (less than 5 at 0’ to 10’ out) off base is NOTHING to worry about.
2) The buzz could be caused be servo binding at either extremes, or access pressure through the control rods. Usually, if you here them buzz, move the sticks back and forth and then release to center. If they buzz, then you’re more likely getting some binding in the control rods. Check for clearance, burrs on the inner tubes, or tight bends/corners.

My .50 cents.....