Has anyone tried this in bigger batches?
I haven't tried the recipe with larger amounts, but historically have found doubling jam recipes to be a disaster where they don't "gel". The version I suggested is a bit more fool proof, if it doesn't gel (try it on a cold plate) then just cook it longer.
Blueberries are the BEST because they freeze so perfectly, and you don't have to bother freezing them flat on trays, just fill up big containers or freezer bags. Enjoy!!