How do I convert 50Hz AC to 60Hz AC using a cyclo-converter?
As per Wikipedia's page on cycloconverters, firstly they are only used for producing a lower frequency. Secondly, they are only financially sensible at megawatt powers.

As for thyristors' ratings, they will be in their respective datasheets.  

A Google search for "50Hz to 60Hz" gives a plethora of options for achieving what you want. There are plenty of off-the-shelf solutions as well as cheaper home-brew methods.