*apologies in advance for my poor artist skills.
Was hard to describe, so i made a few images to help:
left icon = copy, pops up a numbered menu (8 copy slots)
right icon = paste, pops up the numbered menu to select which slot to paste from
the 8 slots for Position are independent from slots for Rotation, for example.
a super nice bonus would be to include additional independent slots for 2d vectors/data like fuselage width/height in the part shape tool. the length/offsets would be an additional super nice bonus
The copy paste data could be stored as part of the craft XML, and have similar use cases to themes / AGs
Users could note transform slots as key positions in the design as part of their craft post, to facilitate mods to existing craft, ex: "The center for the missile rail left is stored in position copy slot 1"