Have you considered adding chilis to your apple butter?
I made several batches of crab apple jelly with chilis and posted photos in this thread
https://permies.com/t/193513/tamarillo-jam#1609010
We served the jelly with cheese and cold meats. It was great with pork chops too.
Stewed apples are a softer consistency than apple butter but I think that chilis could also be good in either.
Seville oranges are in season here so making marmalade at the moment, grated Seville orange zest is really good added to cooked apples.
I find it easier to measure fruit by weight rather than volume - it allows for different sizes of fruit.
For jams and jellies, I prefer batches of no more than 1.5 kg - setting is more consistent. Larger batches are for chutneys or stewed apples when I often use up to 3 kg fruit - too much takes too long to reduce.
The added ingredients such as dried dates; raisins etc can add another kg.
I jot down the spice combos and number of spoons by weight of fruit and whether the fruit was under or over ripe so that I can adjust the ratio of sugar.
We prefer to err on the side of too little sugar - water bathing ensures that the preserves store safely.
