Putting it on the inside of the spider will move it in 6mm, 39mm ain't much better, and 3-4mm is a lot of BB spacers. Your surly rear setup is probably about 43mm. I would get a new BB (107 with 1-2mm of spacers) and then call Surly and complain profusely that they didn't notice this spec change from their supplier. Or make them send you a new BB, but that's unlikely. Also, please tell us how they respond.