Aha, maybe the friend is thinking of compound chocolate and not realizing I use pure cacao. Thanks!

The mold should be at or just below the temperature of the tempered chocolate you're using.  If it cools to quickly you can see bloom as type 4 or even 3 crystals will form.  How much depends on the size, percent, and dispersion of the seed.  Chocolate should always cool slow enough to only allow type 5 crystals to continue to grow.  People commonly see swirling on the chocolate surface using molds that are too cool.

However using compound coating using a fat that only crystallizes in one form it may work as you want to cool much faster than chocolate.

With shell molding, some will chill the already set chocolate shell to allow you to fill with a warmer filling so you do not detemper the shell.  But chilling too much may allow some condensate to form on the outside, bringing on sugar bloom. 

 

Curious if anyone has experience with this as a friend is trying to convince me this is the best method. Chilling the mold in ice slush (eep?!) and filling the mold using a pastry bag and a tiny tip. I have been making chocolate for years and do not feel this would work as the chocolate would be set too fast and have bubbles, and th small tip would clog. But am admittedly self taught, so while I suspect my friend is a bit confused on the matter but just thought I would ask some others to settle the discussion. 

I tried this ice slush in a tray years ago to make shells for cherry filled chocolates... when I had no idea what I was doing and it was nearly impossible to keep water out of the mold. May also have been the way I was donig it. I have settled on either spooning or using a squeeze bottle to fill mold while tapping out bubbles and then cooling after the molds are full, but not freezing due to the condensation.