How to put up ceiling tiles (huntonit) in an irregular room?

[Nizztos]

I will see if I can try to describe my problem in words.

I have a room with a slanted ceiling so I need to lay tiles from both sides so they meet at the ridge.
One short side of the room is narrower. The wall protrudes by about a meter on both sides of the room.
An attempt at ASCII art. Risk that it looks weird with proportional font. It turned out odd. Imagine my x as blank spaces.
________________
| Axxxxxxxxxxxxxx|
|xxxxxxxxxxxxxxxxx-------------
|xxxxxxxxxxxxxxxxxxxxxxxxxx|
=======================
| xxxxxxxxxxxxxxxxxxxxxxxxC |
|xxxxxxxxxxxxxxxxx -------------
|xxxxxxxxxxxxxxxB |
________________

I can easily start one half at A, and when I reach the narrower part of the room, I can cut the tiles to get past the corner and then into the narrower section.
But to lay the tiles so the "tongue and groove" are correct on the other half, I would start at B and then I am not quite sure how to handle the corner into the narrower section. I can't lay the tiles "backwards" towards C. It wouldn't match the "tongue and groove" which is, in a sense, one-directional.

I can't be the first person to have this type of room and lay this type of tiles. Is there a standard method for how to handle this situation?

 

[kasper1]

Measure the room and start from the middle

 

[Nizztos]

Measure the room and start from the middle

No clue what you mean.

If you mean the middle at the ridge, I can't manage to place panels in the "downhill". I can't juggle the panel while I screw it. When I start at the wall and have an "uphill", it works when you place the panels in the row before. If I were to start from the top, they slide out.