A thought: IF the opening at the left side of the image is indeed hangar entrance, then the top surface of the blocks on the right side of the image is some two deck levels above the hangar deck level. Meaning hangar does not go very far forward.
Does anyone have that image of Kuznetsov floor plans? A series of photos perhaps from the ship itself, with all decks, including hangar deck, clearly laid out?
Also, what are the odds that there is a whole large piece missing, to be added, between the large chunk on the right side and the chunk visible on the right side? That could be part of the hangar section as well. One can almost see beginning of an opening on the right most side of the left chunk, just before the mobile roof starts to cover it. The opening might be one of a hangar.
Of course, all that is providing hangar level does start where the opening is. If it starts on the top of the visible right chunk, then who knows how large it might be.
On a semi related note - does QE perhaps have 5 decks under the hangar level? Looking at the cross section, that "lowest deck" may not be a deck at all, as it appears slightly shorter, plus there's literally nothing underneath it. While on Nimitz class there's a visibly thick section underneath its last deck, for structural integrity. So that lowest deck on QE may also basically be full of trusses, girders, other structural stuff and some bunks for ballast water, fuel and what not.