Dear owendavidj,
Making sure that the temperature of the milk is 110 degrees before adding the starter is essential; anything higher than that, the starter will die; anything much lower than that might not be warm enough for the starter to grow. As I have posted, and as I learned from the answers in this topic, heating the milk to 180 degrees isn't necessary. Simply heat it to the 110 degrees and add the starter.
Also, since you eat a lot of yogurt, as I do, you might consider the investment of a Brod and Taylor folding proofer/yogurt maker. Link: http://brodandtaylor.com/large-capacity ... 7AodW2sAdg
I have one and I can do 12 quarts of yogurt, in mason jars, at one time!!!!!
The best culture starter I know of needs to be purchased online from GI ProHealth. The link is in one of my previous posts in this topic. It is not sold in a store at this time.