I had 2, traded my 83 frame and fork and pits for a real nice tandem. Still have my 81 in storage in Pa.
Here are a few pictures for ideas to help you decide how to build it
My 81 has been both a drop bar and flat bar bike. The 81 has been both a double and a triple.

Half step + granny with 10 speed rear.

Flat bar with SL-R780/BL-R780 shifters and brakes levers

10 speed brifters and drop bars



My 83 was just a drop bar bike with a double crankset.