Combine in a small heavy saucepan vinegar, wine, peppercorns, shallots, chevril or parsley, and tarragon with liquid or the extra tarragon vinegar. (Reserve the leaves from half of the stalks and put aside.) Cook over high heat until liquid evaporates. Make Hollandaise and gradually add in the herbs.. Very finely chop and add remaining chevril or parsley and remaining tarragon.