How critical is Lateral balance for a sport flyer?

I am just finishing up my TF Contender and I will need to ad 1oz of weight to my left wingtip to get the lateral balance to come out perfectly. The CG balance point is fine.

I balanced everything before I covered it with the battery, servos, receiver and engine mounted. It seemed pretty close then. Now I have the 1oz discrepency.

The total weight of the plane is 6 lbs 11 oz without fuel. The engine I am using is a SAITO .91.

I am mostly curious due to not wanting to cut the covering to insert the weight. If I need to I will.

Thanks in advance for the help.

AL