I would burn both to be on the safe side, I have never done this particular sublimation but I have contemplated it, yes, use the coldfinger to sublimate, think of of a flask with the bottom of the jar (bottom) covering the opening in the flask, you have to fill the jar or cup or whatever glass handy with very cold water, when you burn the crystals/blackmass it will sublimate onto the bottom of the jar, considering the opening of the flask doesn't have a large surface area (not enough room on that bad boy) I would only try this a small amount at a time until you are sure and can do it blindfolded. Now back to the blackmass, in my experience, I2 from tinc has always been blackish/grey with a pretty luster, so I would try the blackmass first and if the yeild is low try the red crystals, Good Luck, and thanks for not beeing an ungrateful bastard.