Reasons placing the simulator is making me want to cry:
1. No two episodes can seem to agree where it's located.
With other locations, like the dorms, the kitchens and Wizgiz's classroom, the zoom in/fade in tends to have a strong percentage of agreement on where in the school they are generally.
The simulation room though...
The very first time we see the simulation room, we zoom in to the north tower (the one that gets destroyed in the season 1 end battle), subsequent zooms suggest the East tower, 'somewhere' in the north-east building (where the Winx dorm is) and in the west tower, where I've assumed the dining hall is. (or under it at least)
I had actually misremembered the order of events from the Season 1 battle and convinced myself the north tower was destroyed before the Winx were transported to Domino, but upon rewatch, the tower is still standing after the teleport.
The one major internal feature that stops me from wanting to put the sim room in the north tower though, is the windows.
Big curved and a little swoopy. Like a much shorter version of the windows of the rear towers' lower floors. There is nowhere on the front towers that have similar windows, the closest is, as far as I can tell, just a fancy open air walkway around the tower's middle-ish area.
And then there's season 4, which is the first time we really zoom in on the rear/east tower, but also the first time we get to see anyone going from the sim room to somewhere else:
(I have figured out recording! sort of. the splice is just the story of the Black Circle being chopped from the 402 opening)
This sequence cements the idea that at the very least the sim room is definitely in the north-west building, but further, that the sim chamber is on the lower levels of the rear/west tower.
While the group leaves and turns left out the door, the corridor they walk down has very distinct widows on their left:
These windows are closer in appearance to the windows found on the outer sides of the mirrored buildings:
Again we're seeing a case of the internal size doesn't match the exterior, but the scene does have some "internal logical consistency."
So at the moment I'm going to keep working on the assumption that the sim room is actually in the lower floors of the rear tower.
That the window we see from the inside is actually a smaller window separate from the external windows we see, because there is a hallway that runs along the outer wall from the open air hallway door mirroring the external staircase up to a landing (where it exits out the rear facing door,) and around to the other side, down a matching staircase and into the ground floor outer hallway.
over all I'm currently imagining it looking something like this:
Please ignore the fact the red dome indicating the mvr chamber is so far forward in the left half of the picture, I forgot it was sitting directly under the windows and there's only so many times I can redo things from scratch because I wasn't thinking and closed my files losing access to individual layers.
Also, yes, based on external measurements, I'm working on the idea that there are 2 internal hallways on the ground floor and lower mezzanine, separating two series of classrooms.
and the similar testing room without the mvr chamber being in the other rear tower's base, in basically a mirror but with more seating. Partly because that one does zoom/fade in to the other rear/south tower.