Who prefers just knit, fast and regularly, usually selects other patterns. This one is evidently a little puzzle.
A small smart puzzle, may I say.

If you admire any visible form of the Structure (math, anatomy, construction, music, etc) - welcome to the club ;) Wish you to enjoy as I was (or even more).

My palms are not big, but pretty wide; so I’d better add a couple of sts between hand section and the next part. In this case the mitts would be absolutely perfect.
Isn’t it a reason to make another pair?

The thinner needles (2,5 mm=1 1/2) were used in the thumb parts: I feel my fingers (thumbs especially) often chilled. “The thinner needles” i.e. “density”, i.e. “warmth”.

Some more numbers:
provisional CO = 19 sts
length of the hand section = 45 rows = 18 cm
total number of sts in the sideways setup round = 33
thumb’s around = 16 sts, thumb’s length = 24 rows = 5 cm