12>8>6>4>3>2>2>2>1>1>1 is roughly the xp return sequence I encountered when I tested.If my memory serves me, you get full xp on 1st craft and minimum there after.
I have the window open and each unit is giving 1xp. Same with forged iron
Thought this was taken out of the game.
It's been in and out to one degree or another at different times in the past. It will be interesting to see how it all settles for the final version. I honestly have no idea where it will land it has changed so many times.