Okay,
I have read this here before about low acid tomatoes and I have to say something.
It is not the difference in the acid in a tomato, it is the amount sugar in the tomato that makes them SEEM low acid.
As far as hot water bath canning instructions, get PH paper and check the acidity if you are worried.
The old canning method where you boil the mixture and just put it in the jar and let seal on its own is called the, "open kettle method".
If you put jars in a water bath with the lids on it is called the, "hot water bath method".
If you pressure cook them it is called just that, "pressure cooking".
I personally DONT recommended the open kettle method.
The other two have their place and should be used accordingly.
I dont give any other advice on canning.
I have my own time tested methods and I dont need some lawyer knocking on my door.
I spent my entire life growing up around canners and preserving food, it wasn't a hobby it is how we would feed ourselves.
Two big canners going all summer long in a house without air-conditioning.
Worth