What if the two of you came up with a list of Spectrum
Glazes that you think would be good for Sax to carry?
They could "test" the selections that you suggest to
see how well they do. I am all for the red myself as I
was unappy with the Amaco reds (when I used my kilns
with over head vents). Take a look at the Sax glazes
too - They may not want to dulpicate colors that they
offer. I only used the Sax glazes in sets - and was
happy with those. My primary glaze brand was Amaco --
and I ordered wherever I could get the best price.