Hey Paul, how you been? I usually balance mine laterally from an in flight test.

First make sure that your elevator throws are matched as this will make a difference in the test.

Second go up to a little altitude and pull the power back to idle an enter a vertical downline with power at idle.

With wings level and power at idle let it accelerate a little then quickly apply full up elevator. Do this routine a couple of times upwind and downwind to be sure you get a consistent result. Make sure your wings are level and only use elevator for the manuver. If you have a heavy wing it will show in a turn toward it.

I like to use blenderm tape on the wingtip with a dime or quarter to start and see if it gets close enough wighout having to go with lead.