I went to a tire store and asked about the used lead weights that come off of tires and the guy handed me a 5 gallon pail of them. I melted them down with a small torch into a tuna fish can and bolted it to the fire wall. Cost? ZERO. They melt quickly hold the clip with pliers. It took 4# to balance. I have since moved the servos to the CG area to see if I can reduce some of the weight.