msycamore said:

... I simply cannot understand how you fine adjust the positions of the subtitles in frame, it seems there's only x and y values for left, center, right and top, baseline and bottom, not small pixel adjustments.

(x, y) positions the text by pixel coordinates, unless you set either of them to -1 in which case the text is centred. If you check my script you will see that for most of the lines I centred x, and set y manually:

subtitle ( \
text="Going somewhere, Solo?", \
x=-1, \
y=370, \
first_frame=70663, \
last_frame=70698, \
font="Franklin Gothic Demi Cond", \
size=36, \
text_color=$ffffff, \
font_width=10.5 \
)

When you centre x by setting it to -1, the align parameter defaults to 5 (center/baseline). If you want the fine pixel adjustments, you will have to set x manually - in this case, the align parameter defaults to 4 (left/baseline).

For the two-line text you show above, I had to set x manually, as otherwise both lines would end up centred horizontally instead of starting at the same indent position.