I have never see a guide to weight tuning, had sc10 for 5 years. Best i can tell you is go to petitrc. Look up their setup pages on sc10. Find a similar track ,grip ,smooth, bumpy. Open up a couple of different set ups and compare where using weight. The great thing about sc10 is that there are tons of set up sheets. Sc10 . Folks usually like weight below tower, weight at triangles, my trucks have responded nicely to added weight
I actually did that, copying Maifield's setup from this exact track as close as I could. It did make it a little more driveable than bone stock. Figured that's as good of a starting point as any, and will go from there. Thanks!