If a price is just listed in materials, do all the materials used have to be of the same type or are we able to mix and match?
You can mix and match.
-Does gold require stockpile space?
No, but it must be physically located somewhere, like all other resources. It needs to be accessible for theft and looting, and this seemed fairer than having a hammerspace inventory that a dignitary in some backwater village could get his hands in.
-How do I acquire horses?
Stables allow access to mounts, and horse cost is a relative value of how expensive each mount is. A technology will allow a horse farm, which will make stables more efficient at the cost of villein labour.
-How do I acquire Masons?
Build a Mason's guild in a town. Each level provides a mason.
-Do we choose which troops are levied to the Emperor, or does he?
You choose.
-Is there a minium levy that I am required to provide, or is it simply 50% of whatever I have?
50% of whatever you have, defined by upkeep cost.
-How are vassal levy requirements determined wrt irregulars?
irregulars are included in the count.
-Can peasants be moved between farms and quarries within a given year? If so, does this alter crop yields?
Yes. If a peasant doesn't spend all his time on a farm (even if it's just one month) he doesn't contribute to farm yield. I will be as efficient as possible with this, but I didn't want to have to calculate some sort of diminishing returns from only partially worknig fields.
-Are all taxes paid in September of every year?
Yes. Both to you and to the emperor.
Hey, just a couple of questions. Firstly, how 'fantastic' is the setting? Is it low fantasy or high? Are there fantastic creatures like dragons or vampires? Could a controllable character be one of these creatures?
Spoilers.
How do I actually create soldiers? How long does it take? How long does it take to raise a pre-existing levy?
I can't believe I forgot about this. This comes in a number of steps. First is the armament step. Your new troops will acquire their gear, be it through using up the production of your ironsmiths, bowyers and stables (in towns) or by you providing them with gear from your stockpiles. This can be any number of months, depending on how high a demand there suddenly is. Second is the training phase. This requires space in a drill area (found in castles), each soldier requires one month per base skill level for their rank (levy take one month, sergeants take three...). This counts against the farm yield I mentioned above. Once all training is complete, you will either have a standing army to do with as you like, or an irregular force who will go back to their day jobs, train at weekends amd occasionally do a shift of guard duty.
Levy are able to respond instantly to any attack on their holding, even if stood down. Mustering the levy for a campaign takes one month.