I applied about three coats, allowing to dry in betwixt each time.
After staining (try on a piece of scrap) the color will appear blotched and dull. Sand or scrape smooth to remove whiskers and apply your final finish to see what you have, it may not be nearly as bad as thought. On the stock, just take and flood the surface of the wood with distilled water, this will accomplish the same purpose to determine what the wood will look like once finished with oil & etc.
The vinegar stain works on the same principle as aqua fortis. The dissolved ferrous metal and weakened acid penetrates into the wood fibers, changing the color chemically by going after any tannins present, resulting in differentiating the color of soft and hard figure in the wood.
Note: After the vinegar stain, the stock will need to be washed with a solution of fresh baking soda and distilled water to kill the ascetic acid in the vinegar, (it should foam a bit when applied) otherwise, the acid may continue to work and darken the wood even more.