As explained in my last e-mail and also by phone with Viroj I confirm you that each production of our color 591456 tonality can be different from the previous one. As already specified the main property of this color is that starting from a rod of different intensity the final result after working is the same.
You can also look at your color chart of color 592212 where starting from different tonalities of rods, the beads result (after working) are all included in your quality range.
The importance of QC is not the starting tonality of the rod but the range where the bead have to be included.
All our tests are made comparing the resulting beads with the ones included on your QC a part from the starting tonality of the rods (the beads resulting after working is very important not the cold rod ).
In your question n°4 the answer is yes it is, rubino oro belongs to a particular group that we can call "changeable" (like rosso trasparente).
In my next e-mail I'll send you pictures of the different flames that allow us to obtain different results.
Always at your disposal.