I built a ladder body almost exactly like the one described on this site by 5kidsracing. The rear axle is 5/8” from the back. There are two rows of six 1/4” tugsten cubes behind the rear axle and a row of six and a row of five in front of the rear axle. It’s the exact configuration he recommends. The car weighs exactly 5.0 oz which is the limit. The problem is that the COG is just slightly in front of the rear axle. It ran really well when I tuned it on a flat surface, but it bounced around quite a bit on the track. I’m assuming this is b/c the COG is so far back. What would you recommend?