I doubt many would claim that thicker wire is detrimental to the sound.
However we look at it, the narrowing of the conductor at the end is the weak spot. Theoretically, it has to be. Practically, maybe negligible. But many might say that for common cable lengths (2-3-4 meters) it is all negligible anyway. So, if we are talking in technical/calculations terms, decreasing the wire gauge must be of some importance. If we are talking about sound quality, it may not be important at all and the only way to find out is to listen to it.
Which makes calculations redundant and those who claimed that cables have to be listened to and not calculated, sort of, right.
How thin is that last connecting piece on the 0 AWG wire allowed to be before it can be considered a fuse? Should I ask that on some fuse thread? People there have some strong opinions about similar filaments' impact on the sound.