I think we have 2 different approachs here.
For the Dr Pepper, if adding the 12g NaOH /50ml Methanol, I would try half a litre of glyc. If you have some KOH that would require 16g, but if only 90% then 18g. I was following Dave's coment "Suggestion, add the correct chemicals to nuetralise the oil (use a minimum of methanol) to the glycerol you are going to use for the wash. That should leave the oil dry and neutral. I think you would be better off using potassium for the whole method, using sodium for oil that titrates so high is bound to cause issues."
I think Richard is refering to what he used for a batch of his oil previously. We know yours titrates at 12, so just using 1g/L means you would have to repeat the process 12 times. My guess is that Richards glyc also had a significant caustic content, and his oil only titrated at 7.