It sounds like a big splitting hair problem... My first question would be what does it matter? I can't imagine it being that big of a difference... Unless it's some very special race specific application you're needing and even then...
What I’ve read so far indicates there might be a significant weight difference between the 8.75 and 8.25, and disc or drum may tilt it even further one way or another, so I’m looking for actual numbers.
I’m also trying to figure out if discs or drums are heavier, all else being equal.