Did you use a flatmap to build this? If so, have you got a link?
EDIT: Can't find a flatmap that's high enough and where the water doesn't freeze.
How did you make it? Gen map or flatmap?
How high is the structure? (the above ground area)
The structure above ground is 84, and the below ground portion goes to lowest bedrock.
I did not use a flat map. What I did was I built several modules (about 8 in total) which were things like 1 side of one unit of the main nave, one side of the front facade with a tower, one side of a side facade, one side of the altar apse, one side of a corner junction, etc; I then pasted the modules together into the proper configuration based on the pre-designed plan, and then I did the same process with the crypt and pasted it in, and then built half the gardens, and mirrored the above ground spaces.
The modules were built on undergound platforms (which were flat) that I cut out of the land using Worldedit's "cut" function. The world was a normal survival generated world. We did have water-freezing problems, etc.
If you are planning something massive like this, I beseech you to use world edit tools, or you will spend 40 times the amount of effort you should (this would have been a 2 year project otherwise); and if you are using world edit, you would not need a flatland map.