The period slider doesn't seem to work for any of the Z strategies. I assume that's because they have proved to be best suited for the timeframes that are assigned to them.

Is it possible to change their timeframes with additional scripts, or ini files, or some other way? Would it be a bad idea to test other timeframes?

I'm just curious because I look at charts of various timeframes and they can be so different from each other. In my "untrained" mind it seems that many of the trading strategies would work regardless of the timeframe.

Except for Z3, the strategies work also with other time frames, but they work best with the selected time frames. Therefore the time period is fixed. Other time periods would also require modifications and different parameters.