Hello. I have a marmalade recipe that I like that calls for 2 lbs Seville oranges and 2 large lemons. The fruit are simmered whole in water until soft, then sliced and boiled with sugar. I would like to use this same process but different citrus fruits, like meyer lemons or grapefruits, instead of Seville oranges. Would the marmalade still be safe to process in a boiling water bath (5 min in sterilized jars)? It seems like it should still be acidic enough, but I can't find any information about the acidity of different kinds of whole citrus fruits. I also reduced the sugar in the recipe to taste, but from what I've read the amount of sugar does not affect the canning safety, and the marmalade gelled just fine when I made a small trial batch. I've found other recipes online, but they don't use the whole fruit, which I prefer. Thank you.