Talk

Yep lemon's in there, juice of one small lemon. Does that sound about right?

I add lemon .....but assumed this would be in the recipe OP is using?

or lemon juice.

Sorry pressed post too soon!

Apricots are very low in pectin which makes jam set so you may need to add pectin or another high pectin fruit like apple.

Weight is after stoning
....so amount of fruit cooked is equal to amount of sugar cooked.

I would weigh them after stoning. IMO It is the sugar/juice proportions that matter. That way you have more fruit flavour per Kg sugar.

Lucky you to have so many fresh apricots. I looked in my recipe books and it doesn't really matter about the weight after stoning them. 1kg fruit + 1kg sugar. Enjoy the jam.