We finally now know that the sherry Frasier is dispensing is Harvey's Bristol Cream, as you can see from the distinctive blue bottle and the label branding shown on the glass table.
This episode has essentially the same plot as a season 4 episode of Cheers, in which Sam lends Diane $500.00 which she uses to buy a rare book. When Sam questions her on spending that much on a book, she lets him keep it until the loan is repaid. Sam then accidentally destroys it.
The Act 2 title card, "A Moveable Face," is a play on "A Moveable Feast," the title of Ernest Hemingway's memoir published posthumously in 1964.
The first title card reads "Spa vs. Spa" which is a word play on the "Mad Magazine" comic strip "Spy vs. Spy."