What is the best approach for determining where to set the CT threshold when you have >15 samples? Is it best to go through all of them, looking for a range of best fit, and then just choose one value that fits all of them?
FAQ ID -2705

The best way to set the threshold is to make sure that your PPC values are between 18 and 22. I would look my first PCR Array, set it so that the PPC is at 20, and see if the same threshold fits for the rest of the arrays.