It seems that Kosar (and myself) are guilty of the same thing - advocating a process/procedure that we had not independently verified. Your findings that DAS does not sufficiently harden gum to hold pigment has been confirmed by fellow APUGer and Gummist Rob Shaffer who has been conducting DAS/Gum tests and reported his findings in the November meeting of the Historic Photo Processes Forum. The good news is that he found that DAS works well with casein and Rob will soon be posting his findings here. I am most interested to learn of the results of your experiments using DAS with synthetic colloids.