No, use the entire packet for a single dose of SO2. The formulation (therefore dosage), can be affected if the granules absorb any moisture.
Can I break the Inodose tablets in half to deliver a smaller dose?
No, do not break the tablets for smaller dose additions. The combination of potassium metabisulfite and potassium bicarbonate may not be evenly distributed in the tablet. The tablets are available in two sizes to help give dosing choices.
I added a 5 g granule sachet of sulfur dioxide to my 60 gallon barrel. Does this mean I have 22 ppm of free sulfur dioxide?
You have 22 ppm total S02 added. The amount of free depends on pH, residual sugar, solids, etc.