This might sound like a dumb question, though I have to ask/make sure (as my experience with prussic cords is extremely limited...) - It is the case that generally you need a larger diameter prussic cord for a larger diameter climbing line? - Therefore the smaller the diameter the prussic cord is - the greater the chance of having trouble tending and binding sooner?
I've been doing some Sticht testing...
Just as Brocky suggested - the larger black ring allows too much slack to dissipate from the upper wraps to the below eyes (and therefore it will bind sooner)...
The smaller ring (swapped places with the black ring) in its place is better for maintaining needed slack for the upper wraps.
I tried a biner in place of the black ring, though I don't think the bend radius is as large and smooth as the ring - therefore the the action of the hitch is just jerkier and less reliable.
This did not tend - the black ring put extra tension on the prussic and prevented it from gaining any slack for the upper wraps to loosen (and the hitch to tend). I never tried it with the rings swapped around - so it might be better with the smaller ring in place of the black ring (plus I had to thread the climb line through the black ring).
This last configuration worked the best - I might even begin to try it during my working day - it keeps the black ring tucked down below, neat and compact. The small problem with this configuration is that I've had to thread the black ring through the rope as part of it.
If anyone could suggest anything that might clip on (like a quickie or shackle/snap) that might match the large, round radius of the black ring? - I'd love some suggestions.
I'm still just using what equipment I have, trying to get best results, finalising testing to know best things to get before maybe buying anything.
Edit: I just realised that Louhut has already covered a lot of what I'm testing here back in 2019. Apologies for repeating.