I used Hartley's Ma Made purchased from Williams-Sonoma. I was told by an associate there that the thin cut makes the best marmalade.
After the jars and lids boiled for two to three minutes, I put them on a baking sheet lined with a cooling rack in the over to keep them warm and dry.
After boiling to the correct consistency, I tested the marmalade on a cold plate to see if it had jelled. After letting the marmalade rest for a couple of minutes, I poured the mixture into each jar and added the lid. Finally, I let the jars come to room temperature and cool down.