I recently made a few batches of marmalade (each batch made about 8-8oz jars) using meyer lemons. One was made entirely of the lemons (and I used the whole lemon, sliced thin), one was made 2/3 lemons, 1/3 blueberries. I did not use packaged pectin, and kept the sugar low (about 2-3 cups) because we like a tart marmalade. I canned the jars using BWB.

Is it okay safety-wise that I used less sugar? I assumed that the high acid content would compensate for the lower sugar. Is that correct?