I haven't tried the ppc64 installation. On my iMacG5 it goes a whole lot quicker than on my iBookG4. I would say maximum 1 hour.
MintPPC is a rolling release distribution, which means that you will get these updates in the current system. All you need to do is upgrade your packages.
More info
Can you be a bit more specific please? When do you see a blank screen?
Installation of Debian sid with the latest image (19.4.2020) should be possible. Perhaps you have a video card that is not supported?
No, there are others who have had no issues installing Linux - Ubuntu, MintPPC, Debian, etc on a G5 Quad with the nvidia cards.. I am not sure if nvidia cards have their own parameters ?
#958835 - installation-report: all ok - Debian Bug report logs
bugs.debian.org
@Macbookprodude Did you try swapping DVI ports?
Try disconnecting everything from the machine besides the mouse, keyboard, and monitor. Are there any other PCIe cards installed besides the 6600?
I tried that too, and that did not work. I am using only the nvidia 6600 256MB card.
apt install xserver-xorg-video-nouveau
@SnakeCoils take out that FW800/USB combo and try again. It seems that you have a problem with the hard drive. Is it a SSD? Maybe you have to update the firmware. I read that somewhere with the same problem as yours.