[UriF]

Thank you very much for your comments!

[+] About the PID Gains, I'm totally clueless as to what to set them to, so I just set the P variable to 0.1 and zeroed out the others. (Perhaps this was causing the unexpected results when I directly used the Gyro as input, because the output was always @ 100% all the time); Could I set them to something more appropriate?

[+] Should my current method work when I fix the Angle correction routine?
or should I use the 2-PIDControllers method? It sounds odd to me that two PIDControllers could 'collaborate' together, when running independently.