How long did the strings last before going dead?
Couldn't justify the lifetime. I had them on only for a couple months or so. Not because they've gone dead, but I just couldn't stand the flopply low-B.
Don't get me wrong, I'm aware nylon tapewound strings are inherently low tension and flexible. AAMOF, I’ve had D'Addario Nylon Tapewound ETB92-5 on my other Ibanez 5 string fretless (same scale length) for 5 years. Not to mention my main (fretted) 5er has 40-120 Dunlop Super Brights, which 45-125 set are considered by most as already flexible roundwounds. Hence, handling low tension and flexible strings, which low-B's always have the lowest tension, had never been a problem for me until I got these Copper White Nylons.
The fact that I love D'Addario Nylon Tapewound so much on my fretless, which are still going nowhere despite they've been on for years, is what led me in getting another nylon tapewound set when I got another Ibanez fretless. But, since this newer fretless is a semi hollow-body bass, I thought it would sound even better if I put on the Copper White Nylon Tapewound set.
My conclusion of the problem I was having with the Copper White low-B being too floppy is due to its taperwound construction at the ball end side. Thus, making the already low tension and flexible string even floppier. Had the low-B wasn't tapered, it wouldn't be as flopply, and I would've kept the Copper Whites on. FWIW, D'Addario tapes low-B isn't tapered at the ball end side.
Since you seemed not going to get these Copper White Nylons for a 5 string, most likely you would have a blast playing them for a long time.