I haven't tried the D'Addario tape wound B-string! I can't say.
For the Labella 760N, I do not find the B string excessively floppy. It is somewhat floppy, as tends to be the case with B strings in general, but I don't find it objectionable. For what it's worth, this is, more precisely, the 760N "extra long" set... I don't know what difference that might make in terms of tension, but it was the exact set specified to match the bass.
In my opinion, overall, comparing the E-G strings
Labella 750N: too floppy, don't like
D'Addario: feels good, more floppy than ~45-105 roundwound, but manageable. I would guess feels more like a 40-95 roundwound set maybe.
Labella 760N: least floppy, maybe no more than ~45-105 roundwound.