I have never used K-Meta, but I assume it is basically the same as Potassium Metabibulfite, which is the same as campden tablets. One Campden tablet equals 1/8th of a tsp. of Potassium Metabibulfite. For inocculating your must, you use 1 campden tablet or 1/8th tsp. of Potassium Metabibulfite per gallon.
All of the instructions I have seen recommend NO MORE that 1/8th tsp. per gallon when racking or stablizing. Although this is probably fine for stabilizing, I think it is a little heavy for regular rackings, so I only use 1/4 tsp. per 6-gallons and rack every 3 months. Obviously, the best way to know how much to add is with a free SO2 test, but that can be difficult and expensive.
For sanitizing, I use 1 tsp. per gallon and store the solution in a 3-gallon carboy with an airlock. That way the solution will last for several months.
Hope this helps, but if you need clarification, let me know.