Tomato sauce question
Hello all. This summer I have been saving all my tomatoes in the freezer after coring them and last night following into this morning I finally thawed them all, peeled the skins and processed them into 27 cups of tomato sauce. I'm following the Ms. Wages tomato sauce recipe which calls for 10 cups per packet. Would it be safe to use a commercial plain tomato sauce to make up the missing 3 cups to make 3 full batches? My husband thinks I should just add a little more than half from the third packet but I don't want to rid the acidity levels being messed up. My other idea would be to process 3 more cups of whole tomatoes but I already cleaned up from my big processing this morning and I don't have the time for that. I plan on water bath canning. Thoughts?