What is the maximum size of Lego instruction booklets? I am preparing a shelf and, given that LEGO instruction booklets these days are often more like actual little books than the small booklets we had as children, a section of that shelf will be reserved for LEGO instruction booklets.

Therefore, I am interested in the maximum size (width and, in particular, height) that instruction booklets come in so far. To start, I'm assuming a height of 26cm (that's the largest booklets I have here right now), but maybe there are even taller ones?

Note that this question is similar to What are the measurements of the different Lego instruction booklets?, however, I am not asking for a list of all sizes, just for the maximum size I would have to reckon with. Therefore, as opposed to the other question, it is also irrelevant to me which sets are (or will be) there in particular - one level in the shelf that is tall enough to fit in all instruction booklets (standing upright, like books) will last for a while, and if that level (let's say, of 1m in width) gets filled, it's time for another solution, anyway.

EDIT: Note that I am based in Europe and, in case instructions come in different sizes for different parts of the world, it can be reasonably assumed that all of the sets will be bought in Europe.
While there are multiple sizes of instructions and lack of database with dimensions my answer is based on personal observation.

Looking at the stash of my instructions from multiple sets (including several largest Technic models) I can state that the largest dimension I have is of A4 paper size, which is 210 x 297 mm. I'd like to note that this is for Europe based sets. There might be different sizes for other markets as LEGO provides two options for their instructions online - optimized for A4 as well as Letter sized paper.

Edit 1. As masterX244 pointed out in the comments Star Wars UCS sets may have bigger instructions. This review on Brickset of SW UCS set with highest number of parts (75192 Millennium Falcon) says instructions are 42 x 29 cm in size. This is very close to A3 paper size, which is twice the size of A4. 

Picture below, from the very same review by Brickset, shows the instruction relative to side of the box (45 x 39 cm).



Edit 2. JPhi1618 found that UCS Star Destroyer 10030 set has a booklet that is slightly larger - 43 x 30 cm (landscape orientation, including the spiral)