We used to run WKA back in the 80s. Had light, medium, and heavy classes for the entry level stock class. Always had plenty of karts in each. Only time you had to bolt a bunch of lead on is if you chose to run the next weight up class (some would run 2 classes with the same kart). Jr class was one weight with stock engine or a limited modified and age 12 up to 18. Now the tracks around Denver are running l206 with 3 weight classes. Is working well. Seems like this is what is needed for the stock classes.