In my humble opinion,
I believe labs should rotate weekly, as hobgoblin mentioned above they will rotate if shutdown by PD, which I am sure this will happen at least every couple of days due to certain things happening icly.
There should be at least 7 tables in each lab and I believe these should consist of coke/lsd tables for 2 locations. I.e out of the 4 locations 2 labs have 7 coke/lsd tables in each and the other 2 labs have 7 tables each for crack/meth etc.
I think some of the tables are also missing the ability to place down drugs as they are missing the recipes.