Pics please

The rod and window are only part of the equation. Actual width of treatments when stacked back is also essential to consider. Further, the curtain may have enough space literally, yet still look unpleasantly crowded.

If your selected treatment can stack in the 10" wall space, then I would simply shorten that rod such that it extends the same amount past the window on the other side, as the other 3 do on both sides. This is the closest you can get to a consistent treatment for all 4 windows.

If your selected treatment CAN'T stack in the 10" wall space, then we definitely need pics to find you a solution.

I'd also point out that whenever things get awkward due to irregular sizes or shapes, it works well to to reduce the contrast and eyecatchiness of the awkward things. So if you were forced to use a shorter rod on one window, I'd recommend using a very simple rod that blends with the wall and/or curtain, as opposed to a bold or eyecatching one. Likewise, if a curtain has to fit in a space that is very narrow, I'd go for lighter weight, less contrasty fabric to avoid an overcrowded look. More so if the room is already small. Hence the need for pix.