Brilliant, thanks! FYI, anyone else, the system.entryDialog can take min, max, default, and other stuff. And I wanted to change only the timing aspect of the channels, so my quick script became:
private string datain = system.entryDialog("Channel Timing (all channels):",0.005,,channel.channelA.timing)
if (!isempty(datain))
channel.channelA.timing = strToDouble(datain)
channel.channelB.timing = strToDouble(datain)
endif