Okay I found this so far on how the oil is extracted, and a bit more for you..  There are 2 main ways of getting the oil from what I see. (And one that is done through fats and compression, and sunlight.)

 I was a bit off on the absolute thing, because it's done with alcohol, and the steps are different. http://essentialthree.com/blog/?p=376

You should read this entire page, it's very comprehensive, and it give tips for DIY calendula growing and harvesting, juuuuust in case that would be your next inquiry. http://frugallysustainable.com/2012/03/harvesting-preserving-and-infusing-calendula-flowers/

Here is some more awesome info I got from

http://articles.mercola.com/herbal-oils/calendula-oil.aspx

In a study,8 calendula oil was obtained in low yield (0.3 percent) by steam distillation with cohobation from flowers and whole plants. Identified by the researchers were 66 components, mainly sesquiterpene alcohols. α-cadinol was the main constituent, about 25 percent. The essential oil from the whole plant was found different from that of the flowers through the presence of monoterpenes hydrocarbons aside from the alcohols.

The principal constitutes of calendula essential oil9 are flavonoids, saponosene, triterpenic alcohol, and a bitter principle. The useful components of calendula itself include a volatile oil, carotenoids, flavonoids, mucilage, resin, polysaccharides, aromatic plant acids, saponins, glycosides, and sterols

^ that makes it much easier to really figure out efficacy of anything in theory, safety is another thing. I'm sure that if you googled chemical breakdown of calendula in percentages you could find it.

Depending on what you really want from your infusion to do, I can narrow down my searches in Pub Med, there are surprisingly a lot on Calendula. No wonder I found a couple!  I hope this at least helps for now!

If you intend on using this anywhere near your face might I suggest using an oil if your doing the cold infusion method with a lower cosmedogenic value than all these sites suggest (they tend to suggest coconut oil, almond oil, etc. What I would do, is pick and oil to an infuse it with, less than one. Because your preservative Vitamin E is 2. Calendula is already a 1. I might suggest Safflower Oil (Carthamus tinctorius) - 0 . (It's my go-to for natural mineral oil alternatives, make sure you get the right one.) Or even Shea Butter - 0. Either way until I know the application, I can't really make suggestions, or narrow my study find search. Either way, again ty, this is pretty fun!