I tied up flies like this back in the early 90s to imitate LDOs and olive uprights. I can't remember what the inspiration was. Then a bit later on I think it was John Goddard published something similar. I have caught fish on them, but not to the point that they replaced the standards.
All good advice above. My standard set up is straight through leader with 7' from the line to the first dropper then 5' between droppers ie 7+5+5=17. A good spacing between droppers reduces tangles and allows space to retire a dropper if things go wrong. Much less than 4' separation and tangles...
For fluoro Seagaur red label or Invizx are good value on large spools.
For nylon, Maxima ultra green is as good a place to start as any.
None of these are the thinest for stated bs on the market but they are very reliable.
I have one for a 4 piece salmon rod that could be cut to size and only stitch the bottom. It's a little wider than a trout rod bag (6"). Might be an issue if you were putting it in a particularly narrow tube.
Dark blue and green tartan. Yours if you can use it.
That looks like the one. The colour seems a bit distorted by the shadow. They were decent lines. I actually have a still usable Galion slow sink (olive green) in DT6. It sinks a bit like a fast glass.
And I still use one of those fly boxes.