You should be using the random method and not wiggle. Wiggle works with the numbers that you put into the script in a relative manner. SInce you want absolute numbers, use the random method.
To affect opacity so that it kicks in randomly between values of 10 to 80, the script would be like this –
random(10,80)
For random position points between the vertices (0,0) and (40,50), the script is –
random([0,0],[40,50])
If you wanted to have the randomness occur in intervals then precomp it and set the precomp so that it’s frame rate reflects the intervals. Ensure that you jump into the composition’s settings menu, under the advanced tab and check the Maintain Framerate … option.
HTH
Roland Kahlenberg
broadcastGEMs
customizable animated backdrops with Adobe After Effects project files