Just trying to save you some money and frustration! Go ahead and experiment, but I also found this to be true when doing kallitypes, etc. Our theory is that more = less.

http://www.apug.org/forums/forum216/...atinotype.html

There's a write up on fumed silica. Using it in it's dry form makes it super easy to roll on and it has a dramatic effect on DMAX that makes PT/PD printers consider reprinting their entire portfolio!