Centre the weight, not the box
The lean throws the apex right and the left foot out to the edge, so a mark centred
by its bounding box carries its weight right of centre and looks shifted right, over
an empty top-left corner. Put the ink's centre of mass on the frame's vertical centre
line instead. The left margin comes out smaller than the right, and it must stay that
way.
Vertically, go only half way
The centre of mass sits low, because the feet are wide and the apex is a point. Moved
all the way, the apex touches the top edge: a point carries almost no weight but still
sets the margin. So the mark moves half way from its box centre to its centre of mass.
The numbers
On the mark's 32-unit grid, the point that goes on the frame's centre is x
18, y 16.56 (the box centre is x 16, y 15.7). In a
square tile, scale the mark to 0.88 of the tile, as the
favicon does. In a circle,
scale it about the same point until the apex and the left foot clear the round edge,
about 0.8. Move and scale only: the drawing itself never changes.