Sorry. Can't be done. Spread event testing is best tested by setting the mtth to a very short value (days =1) and then watch what happens in situations that you already know what should happen. If in doubt about what is causing what, put your new event in a new file (and add the file name to the \db\events.txt file) and disable all other events by commenting them out in that file. That way you will know that any effect is a direct result of the one you've scripted.
Edit: you can further speed up the event firing by using the eureka cheat which will poll events daily instead of optimizing their load. Your game will slow down drastically, but the events will be polled far more frequently.