Timers for the login screens are hard-coded, but you can replace the defulat ads with whatever screens you want, just change the SourceResource file name. You can also color the images fairly easily by adding color="#somehexvalue" to the image or the page that contains it.
If you wanna get fancy, you can also change the ShowEffector from OpacityEffetor to some other effector. For example, I changed some of them to ColorEffector to produce a transition from 1 corlor to another.
Download FetishNightfall and check out what all I did. Should give you some ideas
