If you are planning on painting, I would leave them as is and untrimmed. I would also add a couple of nut plate to the tooling hole of the elevator near the location of the weight. This way if you need to add weight, it is simple and can be bolted on.
I trimmed mine based on instruction which made right side leading edge heavy and the left side just near perfect balance. By the time I painted the elevator, I had to add 5.5 oz. of weight to the left side and the right was just right.