And as if by magic.

X socks trekking (for me) are the dogs... In trail Shoes.

In boots (which I only use in winter) I prefer a thicker sock.
The X socks thicker fluffier trekking socks, or the hard wearing socks that Chris uses.

As to sizes..

Subjective opinion.
With modern boots (unlike the old leather boots) I reckon should fit.
If they don't they are too small.

Shouldn't stretch modern boots.
Makes no sense.