re: Arm finger joints

I think it will be fine, and if I were doing this again, I'd likely build the arms the same way.  One thing I would do differently would be to reduce the thickness of the blanks with end arm width in mind so that the 4 pieces would have equal width.  Because I had to trim the width after glue-up, the 2 outer strips are narrower than the 2 inner strips.  At least they're symmetric, though.