Here is the math on the offset, someone can correct me if I am wrong but I believe it is correct.
With the wheel upside down the measurement from the ground to the back of the rim is 7", from the back of the wheel hub to the top of the rim is 4", so the offset is et12.7
I am happy to sell off one wheel, the price is $1,000 plus shipping and comes with 4 free wheels :-)