As noted in my book, the Gazette article containing the Washington petition, including the expression regarding property and proportion, was enclosed in a letter from John Neville to George Clymer that is now in the Wolcott Papers of the Connecticut Historical Society, or was in 2003 or '04, when I did research there.
Furhermore, here's the relevant quotation from the primary source:
“Resolved, That in the opinion of this committee the duty laid by Congress on spiritous liquors distilled from the produce of the United States, is a tax not in proportion to property, and if carried into effect will be partial in its operations and inconsistent with that protection which the laws of all nations, even the most savage, but our laws especially, give to the repositories of a man’s house: and that any person or persons whatever, who have or may accept of any office under Congress, in order to carry into effect said act, shall be considered as inimical to the interests of that country."
I first saw that in the original, in the Connecticut archive, but last night I recalled that it was also published in footnotes to Hamilton's Papers, which were not online when I wrote The Whiskey Rebellion. Thanks to Founders Online, the entire Washington resolution can now be linked (see footnote 6 founders.archives.gov).
Finally on this: suggestions in the thread that the tax was regressive are correct (though it was not a flat tax); a detailed description of how Hamilton structured the tax to penalize smaller, poorer producers and benefit bigger, richer producers appears in Chapter Three of my book, based largely on the unpublished doctoral dissertation of the scholar Dorothy Fennell, which goes into even more detail; a copy of that diss. can, I believe, be bought from UMI