Got given a couple of jars of marmalade in my christmas hamper and am considering doing a small batch of something similar to this. How much would you advise for a 5l batch alongside a kilo of light DME. The jars are 454g so I'm thinking a jar and the DME will be more than enough. I could up the batch to 10l and add a second jar of marmalade. How much pectolase would a around a teaspoon be right?