ANTOTHER PSA: (unfortunately)
endodoc has reported back to me that for his 1299 oil pan the threads on the bolt were 2mm too long to make the washer sit flush and seal. when i designed the bolt, i counted the threads on the original, in order to provide the same interference. right now i cannot explain this unless that i had the wrong bolt to start out with.
i will check this asap when i return and will provide everyone with the same issue a solution for this. i have already changed the drawing and am currently checking with the supplier to a rerun.
i am very sorry guys...