It sounds like you're essentially looking for Ratio by Michael Ruhlman. It has plenty of what you call master recipes - ratios of ingredients for various recipes. It's not just baked goods - also batters, stocks, meats, sauces, and custards. And it doesn't stop with the ratios; there's a lot of additional discussion of actual recipes to make on top of the plain base, as well as discussion of how varying the ratio will affect the result.
There are of course plenty of reviews on Amazon and elsewhere online, but if you like perspective from members of this site, yossarian also reviewed it in a blog post a while back. I also own it and think it's pretty great.
There's also an app based on the book for Android and iOS (thanks, Stefano). I haven't tried it but it looks like the reviews are mixed to positive - not the shiniest app but it does contain a lot of the basic information.
You do not need to update the recipe ;-)
Please remember that the way the ingredients are mixed / prepared might significantly influence the outcome: It does make a difference whether eggs are separated or not or whether eggs are beaten with butter first, butter with sugar or eggs with sugar or even everything dumped in the bowl at once (yes, there are examples for all these types!).
An anecdote: My mom - a proficient baker - had major trouble with a recipe she'd gotten from my dad's family. Should have been light and tall, was always only half the height as the ones the other family members served. It took her years to figure that it did not require separating the eggs and incorporating the stiff whites at the end. Well, it didn't say so in the recipe, but as she always did it that way, she'd just assumed...
Have you tried the recipe yet? If you did and have hings you'd like different, we might come up with more ideas.
As for the spices:
If you are grinding up whole spices (method doesn't matter much), be aware that the flavour might be much more intense than with pre-ground ones. And a teaspoon of cloves and star anise sounds a bit much - IMHO. I'd probaply aim for 1tsp cinnamon, 1/4-1/2 tsp of anise and not more than 1/4 tsp of cloves.
Regarding temperature:
In baking lingo, a "cool" oven is usually around 150-160 °C - that would be about 300-320 °F
Best Answer
There is no such reference. In the strict sense, hydration levels are only strictly defined for non-ennriched breads (those without dairy or other sources of fat).
If you want, you can calculate some kind of hydration level for enriched breads, but they become less informative. One option would be to count the whole weight of the fat/dairy as "hydration", the other option would be to count only the water proportion of the product you are adding. I would generally prefer the second one, but it has the problem of getting very misleading when the fat proportion goes up.
Both methods don't create reliable comparisons. For example, if you have a bread at 70% hydration, where all the hydration comes from 700 ml water, a bread at 70% hydration where you are using 795 ml milk, and a "bread" at 70% "hydration" when using 4.1 kg of butter (!) will be really different in their behavior. Similarly, a dough with 700 g water, or 700 g milk, or 700 g butter will not behave the same.
You will get closer to comparability if you also track the fat amount added, that makes it of course also complexer.
If you still insist on calculating something, here are the numbers for the water proportion in the liquids you asked for (needed for the "second method"):