A slight re-calculation of the sizes, I forgot to remember the whole need to be odd numbers so there is a middle block. So makes the each side 1 block bigger from 16 to 17
So - 1 block for wall fence between atrium and corridor, 3 block wide corridor, 3 block thick wall, 7 block wide wing, 3 block thick wall = 17 blocks. Doubling that for both sides then the total area for each wing bit would be a+43 by a+43. I think the Atrium needs to be a reasonably sized but not huge, if we say make it 21 blocks square it makes each wing area a nice round number of 64x64 blocks. We said before about making the corridor between the wing squares 9 blocks so, assuming my maths is correct so all of this, is 64 blocks for wings 1-4 + 9 for corridor + 64 blocks for wings 5-8 = 137 blocks.
The front of the house with the entrance and stairs doesn't need to be so big but is somewhat defined by the room we will need for the stairs. However if we guesstimate that if we make the communal rooms 32 blocks that gives the front to back dimension of the build 64 + 32 = 96.
So that makes the whole house 137 in the east-west direction and 96 in the north-south. Which is HUGE! maybe too big? For some sort of scale the total front print of my personal build is only 73 x 73.
On the other hand I think, as the saying goes, go big or go home!