Still waiting on spokes, so I proceeded to complete the front derailleur installation.
The issue was / is that the TSDZ2 moves the chainline so far outboard, I couldn't find any derailleurs that would go that far, mostly because the
manufacturers don't generally market front derailleurs by publishing the data on just how far inboard and outboard they may go. So, I blame the manufacturers for my having had to do this!
I started by selecting from among all the "braze on" type clamps and derailleurs I could find that might possibly work - and found it bizarre that none of the clamps and none of the derailleurs seemed to be made for one another. ... I obviously don't yet know what the market intends one to do here!
At least the derailleur I chose - a new Shimanno SLX FD-M671 "3 speed," dual pull type - was only $6 and change, delivered. I chose it because I figured a derailleur designed for three chainrings would have more "throw" than one designed only for two, and because it had what looked to be the easiest mounting strategy - like it's designed to be butted against a part with a straight edge permitting up and down adjustment using an M6 screw.
[Below: Right hand view of the "braze on" mount for the front derailleur.]
I then trial fit the braze-on mounting ring in various locations and orientations, including rotational position, height, and which direction the clamp arms went around the seat post (that is, "which end should be 'up'?"). I had to make it so that the clamp didn't interfere with the rear brake control cable, which limits rotational position. In the end, I chose an orientation that put the mounting tang in front of the seat tube.
[Below: Left hand view of the "braze on" derailleur mount.]
I then got the chain out of the way and figured height issues. With the mounting ring as low as it would go, the adjustment still had to be lower, and I also had to factor in rotational issues in the longitudinal axis. So I settled on an aluminum rectangular bar coming aft with two M6 screws attaching it to the mounting ring. This would permit an aluminum bar to project rearward sufficiently and then height would be about right if the clamping screw were centered in the AL bar. I left cutting the length and making the two screw bores until after the rest was ready to ensure it would all work together since any rotational issue with the mounting ring would change the required length. And, the mounting screws would be better projected from the rearmost (centerline) as they proceed outboard.
Then, there was the question of how to attach to the clamping ring? It has a curved tang?! WTF is THAT all about?! I never found any good reason / excuse for that curve - no pictures, no text, no matching derailleurs designed for it - nothing! I also couldn't find any that had flat tangs?! WTF is up with that, too?! ... So, rather than waste time on something I cannot change anyway, I got on with it.
This meant that there had to be a curved part on BOTH sides of the clamp tang, one convex, the other concave, and within the slot, two M6 fasteners would go. ... OK, with that decided, now what?
The inside radius of the tang was somewhere between 4.5 and 5mm, which meant a 9 to 10MM round part could be a starting point. I took a nominally 10M diameter stud and whacked off both ends and mounted it in the mill's vice and then faced off just less than half of the diameter, giving one flat face and the other half round. Then, while still in the vice, I drilled two holes so that there would be rotational stability in the longitudinal axis (that is, so it wouldn't rotate like a bicycle pedal).
I drilled these two holes anticipating threading them with an M6 X 1.0 tap, however, in looking at the part after drilling the holes, I realized that tapping them would leave insufficient strength! It was then that I realized the holes were barely big enough for an M5, but that two M5s would do great, so I switched to M5, the only issue being that it was now too late to thread the part for M5 X 0.8mm, so nuts would have to do. (Either that or make another part.)
The other side of the curved mounting tang had a radius of around 8.5 to 9.5mm, or, the same curve as the circumference of a 17 - 19mm bore. So, I selected an end mill in that range and cut an aluminum block, edge on, slightly offset from one side so that it'd be as wide as it could be toward the seat tube. I then took it to the bench grinder and trimmed down one edge so it'd fit the mounting ring's shape perfectly - got it pretty darned close. ... And then I enlarged ONE of the two mounting holes which would provide for some rotational adjustment of the bar that gets bolted on since the projection of the derailleur rearward was going to have an effect on getting it rotationally spot-on, so the outer chain guide's inner radius matches the same center as the chainring itself.
In the picture below, you can see the steel half-round inner radius part with the two M5 holes laying on top of the spacer that has the outer radius of the curved mounting tang, and its two M5 holes, one enlarged for rotational adjustment of the rearward projecting bar shown above.
The last fundamental to determine was the thickness of the block that mounted to the outside curve of the mounting ring's tang - that part determines the ultimate offset from centerline of the derailleur. ... Some careful measurements were made. I adjusted the derailleur all the way inward, measured the offset from its mounting tang to chain position and compared that with my measure of offset from centerline of the inner chainring to the outside face of the curved mounting ring tang. I then subtracted 1/2 of the chain's width and the thickness of the horizontal bar that the derailleur itself would contact and mount to, and that gave me the thickness of the spacer that mounts to the mounting ring's tang... I decided to make it a tiny bit thinner so there'd be SOME adjustment room!
I then took all the pieces to the bench grinder and "softened" the edges, as you can see in the above images, and assembled it all together. Here's the backside, showing all the parts:
And here's the finished assembly - minus any painting or whatever:
...I can't mount it yet because the longest screws I have on hand in M5 are only 40mm, and I need 45 - so, waiting on that, then I'll mount it up and see how well it works!