Here’s a rather awkward gif showing a method for the blended pipes in the red section of the above image.
It’s right on the edge for the number of frames, so I was limiting my camera movement even more than normal, hence the clumsy arcs.
I’m not even sure it will load properly, way past my bedtime so if it doesn’t you’ll have to imagine it.
Night, night, sleep tight. 
The gif is slumbering as well.
Ok, it didn’t load, so here is a simplified pre-coffee version.
Yay. I wanted to see this video done! Now to pin it somewhere for all future requests? It looks like the resulting grid was all worked out cleanly. Can we see that? How do you get an even mesh with extraneous endpoints that are created in the intersect function?
Curviloft does a pretty good job of making the mesh neat. The more segments in your cylinders will make the transition smoother, but at the expense of heavy geometry,
I didn’t save the model so this is slightly different.
It’s important to remember that my gifs are only one way to do things and there are always many others. The copy paste option could be rotate and flip or the whole thing could be made in one rather than just one quarter. Other tools can be used, Tigs extrude tools for example. Or even a different tool within curviloft itself, depending on the shape needed.
Are you aware you can bookmark specific posts so you can come back to them later. Click the 3 dots under the post and choose the bookmark icon.
Are you allowed to dry your children’s hair in the tumble dryer!?
Throwing this in as a test of the external link workaround, since gif uploads are currently not working.
Let me know if you open this and it is static.
Stunning, all of it 
Not so elaborate as yours, Box, but I recently developed a Dynamic Component to make the outline of spiral stairs - treads and one, both or no balustrades, (and optional central pole.
https://3dwarehouse.sketchup.com/model/10f64cb1-f38b-4f13-86a5-daacde25c0d3/Spiral-Stairs-Dynamic-Component
See if it might be helpful as a starting point.
Thanks John, but it was the ability to bend the detail that was what I was interested in.
Then mine doesn’t help in achieving that ambition. But your methods certainly do!
Did you draw a flat profile, pushpull to thickness, then use a plugin to bend it? If not, how did you do it?
Looks magnificent!
Yes, that’s pretty much it. But I was working out how to get the two balustrades to bend evenly.
So the design on the inside and outside looked the same, rather than one stretched and the other squashed.
Done with Thomthom’s Trubend.
I probably shouldn’t mention, I didn’t save the model as it was only a leaning process.
I couldn’t find the ‘simple’. Hidden in all the details I suppose. 
If I get the time I’ll knock up a gif to show how simple it actually is.
