>Is there a way to force blitz to choose the 60Hz mode?
To answer that directly, no there isn't. It is possible to set the refresh rate through directX, but many, many graphics cards will ignore this completely, anyway. And people don't like it (if done incorrectly, there is a possibility it could damage your monitor).
So every PC game has to instead come up with some way of managing a variable refresh rate, which is a pain, but it can be overcome (see above).
To answer that directly, no there isn't. It is possible to set the refresh rate through directX, but many, many graphics cards will ignore this completely, anyway. And people don't like it (if done incorrectly, there is a possibility it could damage your monitor).
So every PC game has to instead come up with some way of managing a variable refresh rate, which is a pain, but it can be overcome (see above).