First.. thanks for moving the tread, wasn't sure were it should go.....
To answers you question, the biceps lined up fairly well, I trimmed about 3 mm from the top and bottom of the inner piece on both sides. Glued it all together with the ABS glue supplied and then used the demmel and sandpaper to smooth it all together and line it up. I have fairly think arms but was able to get my bicep in after some trimming. Probably could have spaced it a bit better for fit so that there was more of a return edge. But being my first build I am happy so far...pics of the inside of the bicep, still need to finish sand it and test fitting the bicep and forearm...enjoy