RE: I need help with a lateral balance problem.
there are lots of ways to do it.
Get the plane setup so that its lifted by the crank and tail..so you can see how far its off. Obviously if you have a bunch of right thrust in the motor that will mean you can't get an accurate balance from the crank if its off center..
If its not off by much and you have kit experience you might be able to remove some weight from the heavy side wingtip.
This of course depends on your knowlege of building and the way the plane is costructed.
If any of your radio is mounted in the wing can you move it or the battery around? To your advantage....
Otherwise you will propably have to add lead weights to the light side until it balances. Set the lead way out where it can be mounted in a hole or access panel of some type...If you have to add weight a scratch built hatch won't hurt you. Hopefully you only need to drill a hole and glue in a tiny bit of lead..
Might be some better ideas coming along, but this will let you start pondering it. Good luck!