Sorry if this has been answered before but I really doubt it. I'm wondering how much area a castle would have taken. From Curtain and inward only if possible (can't be picky.) Specifically i'm looking for the yard sizes ranging smallest to largest but knowing the entire size isnt that bad either.
For upper margin estimate, largest castle in entral Europe in terms of area is Spiš castle, it's total area being 41 426 m², or slightly over 4 ha.
The number that is interesting for you is the middle yard area, which is 150 x 60 meters, being a reasonable size for a major castle. What makes Spis castle so large is its lower yard, which makes up more than a half of its total area.
I can link you to UNESCO link, but most of the actual data on it are not available in English: http://whc.unesco.org/en/list/620 There is an official site for it, but it fails both website design (taking you back to 1999) and history - the overview you have there is very basic.