34_40, thank you for the pictures. They make the nut issues very clear. The points about the spacers are very good. Making the short ones keyed is a much simpler task than the long ones. Thanks for the insight, guys..
Back to the taper. I finally got the pulley from the vertical head off my mill, and put the arbor driver nut on. When I put a commercial morse taper into my mill (the bore has been spun, so this all has some +/- to it), I measure .697 taper diameter at the face of the arbor driver. With a standard taper that ends at .700, that would give (.700-.697)/.04995=.06006 or a little under 1/16" spacing between the face of the arbor driver and the driving flange on the arbor if the MT2 intersects the arbor flange at a diameter of .700. This suggests a full length taper should work.
Rob's photo makes the length of the taper look to be 2 7/16, not the 2 9/16 from the books. I also keep forgetting the straight section on the end of the tapers. I need to get that into the drawings as well. I'm in the midst of making a tumbler pivot shaft assembly right now, but I think I might try making a taper after that. The compund travel is only 2 1/4", so that should get interesting. I see a file and bluing in m future. I still am tossing around the idea of using a commercial taper with a thread screwed into a home made arbor. An ebay seller named thirddevel sells a MT2 x 1/2-20 arbor with a 3/8-16 drawbar thread. It's kind of expensive at $21.90, but much cheaper than the real Jacobs arbors.