Tipping on alocholic beverages as part of dinner is a relatively new custom. About 50 years ago, Ann Landers wrote that the standard was 10-15% of the bill excluding alcohol. I think a couple dollars per round is more than fair for drinks, and $5 per bottle for wine should be plenty. If the wine is decanted or there is superb wine service then maybe I go $10.

As for asking for a separate wine bill so the waiter doesn't get hit for extra taxes... never heard of that before but I'd be reluctant to take that level of interest in the finances of the staff. That sounds like it would be better handled by lobbying for changes to the tax regulations.