This forum has developed a sort of culture set against necro-bumping, unless there is something really new to add. I've been around here a while, so I've seen it a lot. It never honestly bothers me too much, but I still find humour in some of the responses sometimes.
Anyway, if you like 25.5" scale for low, then good for you! For the longest time, it was the only seven string guitar scale widely available. Personally, it was what I used from 1997-2006ish (well, my BC Rich was actaully 25.4"), but once I had the luxury to try bigger scales, I was sold on the practicality of them.
As the length of the vibrating string gets longer, the tone of the vibration gets clearer. A great deal of this is actually the thickness of the string relative to its length. An ideal string is a set length, tension, and mass, and a negligible width. For low tunings, people tend to use thicker gauges, and then, what happens, is that the string goes from being an ideal string to something in between an ideal string and a long cylinder, which has different vibrational modes, so that overtones are no longer determined by the vibrating string equation, but perturbed by a small amount of error, called "inharmonicity."
Anyway, for a low B, there really shouldn't be any problem with 25.5" scale. I think a lot of us might prefer the tone of a longer scale, in general, for more aggressive musical styles, but the inharmonic overtones of thick strings on short scale lengths can lend itself to sludge/stoner-metal styles quite well also.
Whatever floats your boat, as they say.
