Your resourcefulness is admirable, but I think it more than likely you'll find, as your approach to fingering changes, that the capo is not necessary and impedes your facility on the instrument.
The problem with capos on DB is that the fingerboard is curved and the amount of curvature changes with position. And there are only a few positions where a capo could be mounted.
A padded bendable rod can be tailored to position, but that cannot be done quickly.
Capos are only useful for chords and beyond the typical double stops on E (A) and G string it doesn’t make sense trying to play chords on a DB. Specially without frets.
But nevertheless congratulations to your solution.
Thanks. I've been simply always enjoying the fun in finding solutions to even potential issues. For me it's part of the process called "life". And you'll never know when such an idea may come in handy in another context.
That's well possible. On the fretless bass guitars I haven't used it in quite some time now.
For the start with the DB, the capo might be potentially useful for a bunch of songs where I also have to sing, and where having open strings helps. Which is, on the other hand, why I like to play in D-Standard as we have also a lot of songs with slide guitar in open G tuning.
It's better than "Mark I" but still hard to tighten.
But at my local DIY store I found something even better, something I had in mind from the start.
This is "Mark III":
Works perfectly, even without the wire inside the hose. I only had to sew an additional piece of velcro on the back, since the strap apparently wasn't designed to be wrapped around multiple times.
Mission accomplished.