@pastrychef it looks like some of our comments on here got wiped during the website update (which looks really nice BTW!) but I wanted to update you since you helped a lot with this issue.
So thankfully I have everything working now. There were two things I tried that I believe fixed the black screen boot issue for me. Firstly I noticed that after all of our EFI folder changes, my system definition defaulted to the iMac 14,2, so i changed that back to 18,3. Also throughout this whole process I had the system hooked up to my monitor via one of the HDMI ports on the GTX 1080 Ti. Out of desperation, I plugged in one of the DisplayPort cords to my monitor and that's when it would show the progress bar halfway, go black and then display properly on the monitor. So, I think the research I did in other forums where people mentioned that only some of the ports on the Nvidia cards worked in High Sierra, are what got me to try out the DisplayPort instead of HDMI, and I believe that was the major fix after getting the Nvidia web drivers installed.
Some other random issues I encountered after all the other trouble, that I'd like to mention in case anyone else experiences them. If you have a Gsync monitor, be sure to leave the gsync option
disabled in the nvidia control panel. When I had it enabled, I was getting some weird flickering at the top of my screen any time I would move my mouse cursor around on the screen. Also after disabling it, it helped with the issue I was having with sleep where the monitors would not wake up. But I also enabled sudo pmset -a hibernatemode 0 at the same time as that, so not sure which fixed it, most likely the pmset command.
Speaking of sleep, I tested it, and would let the PC sleep for about a minute multiple times and woke up just fine. I also let it sleep all last night, and it never woke up until I tapped the keyboard which was great. I had a little scare when I woke it up because it seemed like it woke up the screen, then the screen went back to sleep as if it wasn't receiving an input. But, after 10-15 seconds it showed the login screen. Phew. So I'm not sure if that's just how it will always be or if it was a one time thing.
My last thing I'm trying to work on is getting the RGB LED's on my Trident Z RAM to turn on when the system is sleeping. They are the only lights that stay on when asleep, which I've researched and found is due to the system needing to keep the RAM awake in order to wake the system from sleep. So, I'm thinking that, once I get a windows SSD on here, I'll install the RGB software and maybe just disable the RAM lights completely, so I'd rather have them off then be on while sleeping. Thanks again for all the help
@pastrychef, all the troubleshooting we did eventually got me to the final destination, much appreciated!
