Blue Hills, your posts on cable guide have provided lots of viewing pleasure and quite a bit of practical benefit.

I just wanted to post a followup of some work I did based on your valuable measurements and graphs.

I'm running Campy Veloce 10s ergopower shifters. I chose Campy because of the MA (inspired by your brake lever work) and because I thought they looked better on my vintage Motobecane Grand Record.

However, like many others, I want to run them with a Shimano rear derailleur to get the gearing I want. The shifter/mech mix should shift a 9s cassette

However, even with with Hubbub cable routing I found shifting less than adequate. Using the work you did, I respaced my cassette to closer match what the shifters were doing. Where the Campy shifters pulled more cable, I added spacers. On the lower gears, where the Campy pulls proportionately less cable than Shimano, I reduced the spacing. The amount of changed was based on your graph of cable pull. Here's what I came up with:

1-2: 1.89mm The 10/11 free hub adapter spacer is 1.85mm. But it didn't come from Amazon in time, so I used a tiny 9s cog.
2-3: 2.29mm For this I used a single 10s cassette spacer.
3-4: 2.79mm For this I used a tiny 9s cog and a 1mm spacer readily available as part of 10/11s adaptation kits.
4-8: 2.54mm Standard 9s spacer
8-9: 2.64mm Standard 9s + 1mm spacer is perfect, but didn't have another 1mm, so I just used a standard 9s outer gear.

I used 9s cogs to maintain proper C-t-C pitch.

It shifts much better! Up and down between 2-3 is still the most balky. Perhaps adding the 1mm at the end will alleviate an accumulation of error. As will adding the 1.85mm spacer. Finally, my cogs are mixed from different cassettes, so tooth alignment isn't ideal.

I may get a standard 12-36 cassette and grind off the rivets, but I want a custom cog collection, 13-34 "mega-range", so I'll probably keep my cassette.

Maybe next time I'll have DaveSSS machine my shifters