Are these differences due to horizontal versus vertical wove papers, where the horizontal paper wet printed stamps are wider but shorter and the vertical paper wet stamps are narrower but longer; or are they due to dry versus wet printings where the paper wove is vertical and the lengths are the same but the width is wider on the dry printed stamp?
Just doing some researching and found out that all 4 printings of the Pence (1857 to 1862) issues were printed on damp paper, then dried, gummed and dried again.
Dry printing didn't appear until the late 1890's
I am referring mainly to the 1pence & 5 pence stamps
The shrinkage of the paper depended on the type of paper used. The first issue (1857) used tighter mesh paper so the image wouldn't shrink as much. (22x22.5) Handmade paper - various thickness in sheet
The next issue (1860) was printed on printed on a soft paper which caused the image to shrink (21.75x21.75) Mechanical made - consistent thickness
the 3rd & 4th issues, were printed on STACEY WISE 1858 and that paper didnt shrink much (22x22.5) Handmade paper - various thickness in sheet. Depending on the print person, the way they placed the damp paper in the press depicts the size of the stamp 22x22.5 or 22.5x22