I use mLauncher -
https://github.com/DroidWorksStudio/mLauncher
And then I have this energy saving patch in KOReader -
https://github.com/Codereamp/nopowen
In addition, I also followed that person's advice to install Kernel Adiutor and set the CPU to interactive.
I thought my GL4e's battery life was surprisingly low when using the stock software (compared to battery life on my old NST and NGL), but it's been better for me now after making these changes. Just for context, I almost never use my light and wifi is basically always off.