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Fine job with the brakes!
As regards subject of chainset & front mech -
mentioned back in message nr. 2 that there appears to be no room for the mounting of a front mech. we can only think that cycle left factory with single plateau gearing.
note in this photo the positions of the chainguard mounting brackets on the down and seat tubes. because of the way the frame is made and the position of the chainguard, when in place, there is just no room for a front mech.
you mentioned frame is go out for respray. one way you could do it and keep machine "period correct" or at least "period plausible" would be to remove the two chainguard mounting brackets and have a framebuilder braze on a boss to the seat tube to mount a Simplex Competition manual ("suicide") front mech. alternately, you might be able to get by with the clamp-on version as it mounts fairly high on the seat tube...
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