After an extended warm-up at the downstairs café, Country's Geoffrey Zakarian unveils the restaurant's upstairs dining room this week, with its open kitchen, glassed-in meat-curing room, and a couple of minor modifications to the original plan. The $85 four-course prix-fixe menu still changes every two weeks. But Zakarian, wary perhaps of New Yorkers' persnicketiness, has thought better of serving one set meal family style. By greeting guests with a champagne cocktail and amuses, he still hopes to capture a dinner-party spirit, but his opening menu offers four choices per course, from the simple (spit-roasted chicken for two) to the sophisticated (red-wine-poached egg with leek fondue and smoked-eel beignets). You can lead a diner to truffle-roasted sweetbreads, it seems, but you can't make him eat.