You can set the power variables too, I'm not sure if you already tried that, and what total effect they'll have, I do know you can use them for blocking the screen going into standby mode, maybe it'll stop a screensaver?

SPI_SETPOWEROFFTIMEOUT
SPI_SETLOWPOWERTIMEOUT

Also, in the sysem parameters, you can set
SPI_SETSCREENSAVETIMEOUT.