The exact recipe for this is almost foolproof, hence perfect for me. You need one cup of peels, and then equal amounts of pulp and sugar. I ended up with about 3 and 3/4 cups of orange pulp, so I added the same amount of sugar. The peels, sugar, pulp, and a half teaspoon of butter (to cut down on foaming) are put in the pot to boil, until they reach 220 degrees F. At that point, you will want to place a little on a cold spoon (I'd freeze two or three in advance for this purpose) and put it into the fridge. When the marmalade on the spoon cools, it should be thick enough that when you push on it, it wrinkles up a bit. This lets you know your batch has cooked enough to gel. I have to emphasize that it MUST hit 220 degrees for this to happen. Otherwise you'll end up with some lovely orange sauce.
Once the right temperature and consistency is acquired, you can then shut the heat off and ladle the mixture into hot jars and place them in a water bath canner for 10 minutes or so.
When you are done, you will end up with delicious Scottish-style marmalade!