I just bottled about 1 gallon of fortified apple mead, which I think is going to turn out awesome in a year or so. I oaked it and there's alot more brandy than what you're talking about, but even at that it doesn't taste like brandy. Personally I think it might need a little sweetness if you're adding brandy, but that's up to you. I had looked for a Pearson Square calculator or something to see how much it will boost your alcohol level, but with only 6 oz it doesn't seem like it would increase it that much.
Depending on the yeast that you used you'll kill it off with alcohol level and then you could backsweeten to taste.