Same bowls, different

A friend requested some bowls in her household colors, black and gold. With only a week before Val Day I went looking on Delphi's website (they are nearby and ship fast) and found a 3mm black and a 2mm black w/ iridescent gold:

(Unfortunately I think it looks better in photos than reality)

Glass used (Product ID's provided by Delphi, may be proprietary):
B010130 Bullseye Stiff Black 90 COE
B010058 Bullseye Black Opal Gold Iridized Thin
B110038 Bullseye Tekta Clear 3mm - 90 COE

I'm not precisely sure why the gold-on-black is a millimeter thinner, something to investigate later (UPDATE: It's intended for jewelry making, and not general fusing). The blanks are in the kiln fusing at the moment:

I will say, they do look pretty! Unfortunately it ended in complete failure. The blanks looked very pretty, the gold really comes out after fusing, as shown below. I don't normally crash cool, and as such it can take a lot of hours for a blank to cool down. Because I wanted to slump this right away, once the blank was 250-300° or so, I took it out and put it under hot water, which I then slowly changed to cool water, bringing it to room temperature in about a minute. I've done this several times with success. This time, however, I think the plate was hotter than the temperature on the kiln let on; as soon as it hit the hot water a significant crack appeared, between the color and clear layers:

Regardless, I tried slumping it. The results were.... ugly. The bowl was misshapen, cracked, and uneven. It had over-slumped, as well, and almost pooled in the bottom of the mold:

I didn't know if this was some result of the cracking or not, so I tried the second blank I prepared. It was not quite as ugly, but still misshapen. Here they are with comparison to a well-formed Midrealm bowl:

 After staring at a bowl for a long time, I believe this is because of the 2mm gold glass. I suspect it got hotter faster, being thinner, and started to slump prematurely. I slumped another midrealm bowl afterwards just for comparison and it came out fine, with the mold in the exact same place, so I don't believe its a kiln issue. Of course, now I found Delphi has the same glass in 3mm, so there is only one way to find out...