Hi, Alan,
In that I don't have a balance-beam scale, I went about it in a slightly different way, but am hoping that it was valid: I determined the volume of the PWT by displacement (All @68 degrees F / 20C) and then went to three different places locally to have it weighed and taking the average, then divided the volume into the weight. The result: 2.9496. (!) Yikes (!) I figure my accuracy was within a half of a percent on the volume at worst - and if anything I would say I erred on the long side in my measurement. If I reduce / correct the volume by 1/2% I come up with 2.9545, so either way, it would seem I'm right at the far low end of the range, which I would guess is more telling than if it were at the higher end? As long as my method was valid, I'm encouraged by the numbers to say the least...

As to fluorescence, I know it's very subjective (though I do have a very keen eye for color), but thought anything that might be useful as an observation is data nonetheless, even if it's not entirely possible to quantify it.
One other thing regarding the canework, and in particular the outer row and to a lesser degree the inner one too, have almost transparent white ruffles. They are so delicate you can see through them, and that is one quality I only recall seeing in Bacchus (and Gillinder) weights to the best of my knowledge. Not to be contrarian, but I am again encouraged by this detail as potentially significant.
Needless to say, my optimism rarely goes unpunished, so I remain cautious (knowing that as a pessimist, I'd welcome a pleasant surprise over constant disappointment any day!)
And today was a fun one, I can assure you, no matter where it all ends up! Thanks for the refresher on the technical approach - it has been a while since I've applied anything from my school days with any discipline - and was a nice boost to confidence as I doublechecked my work. Yes, it looks good to me... So....?