Can't get light streaks to look same when writing as with wiggle expression

Okay, so I did the "Creating Light Streaks" tutorial by Andrew Kramer and that all went fine. Using the wiggle expression it looks beautiful, but when I remove this and paste the mask path into the light's position or parent the light to a null object and key movement, the streak gets much dimmer, smaller, and you can see all the 6 little masks that Particular is using as the particle. How can I make it look normal, like it does with the wiggle expression, and still have it follow the path (to write words)? I tried upping the size, but it looks bad and I don't know what's causing the dramatic difference. Thanks a lot!