-= V =-
The citadel bends to your will. The runes show you that by unfolding the dimensions in the correct order, a simple rotation of the upper floors will align the tower's aperture with the citadel's window. From the outside the aperture frames the window, and from within the tower the stained glass design can be seen above.
This solution is the most lightweight solution, as it requires little disk space and bandwidth if the new demos are small, and requires only modification to the most recent Quoth pak file (so it can be issued as a patch). It keeps the filenames of the existing demos exactly as documented in previous Quoth guides. There's also an opportunity to be creative with the three new demos. However, it is not a complete return to the original behaviour in Warpspasm (the Quoth demos will still play after the Warpspasm ones) or in Quoth (three new demos play at the start). For this reason, you score 90% completion for your solution.