A perfect Manhattan with bittersweet liqueur rather than aromatic bitters and a balancing dash of sweet maraschino liqueur.
If you can't obtain Picon...
Our Amer Picon sits happily on our bar shelf, unrefrigerated. And we don't have air conditioning. Our current bottle, getting very low after about a year, still retains its freshness. Maybe worry more about your sherry, vermouth and aromatised wine. And yes, a great nightcap...not too strong.