My successes with OCLP and Monterey are as follows:
Late 2012 iMac 21.5" - Full Success. Resulted in a usable system. This system maxed at Catalina. I installed Big Sur with OCLP 0.2.5. With Big Sur, the system was fully functional. Upgrading to Monterey 12.0 Beta 10 was flawless. I upgraded the Big Sur EFI with OCPL 0.3.0 first. I upgraded the EFI boot, then I performed the Post-Install upgrade. Seeing that Big Sur was working fine, I then entered the Beta Testing, and then allowed the Apple Update services to perform the update. The update went through flawlessly. I performed the OCLP EFI update and Post-Install updates and ended up with a useable system. System upgraded: maximum CPU, 16 Gb memory, SSD and upgraded wifi to 2013 iMac AirCard/Bluetooth. (This system seems to run better with Monterey and Big Sur than with Catalina).
Mid 2012 MacBook Pro 13" - Full Success. Resulted in a useable system. The system maxed at Catalina. I installed Big Sur with OCLP 0.2.4, upgraded with 0.2.5. From this point, I used the same process with the 2012 iMac above. I am typing on this system now. Fully functional. The only problem so far is the startup screen graphic quality is rough. Once in, the graphic quality returns. System upgraded: 16 Gb faster speed 1600 MHz DDR3 memory and SSD.
Mid 2011 iMac 21.5" - Full success. I had Catalina (DosDude Patcher) on the machine and had been using it for quite a while. Recently, I installed Big Sur using OCLP 0.2.4 successfully (as per Mr. Macintosh's instructions) and continued using it successfully. Performance was equal to Catalina. I created a boot install flash drive with OCLP 0.3.0 to install Monterey. I first updated the EFI with OCLP 0.3.0 and upgraded the Post-Install files with OCLP 0.3.0 for Big Sur. Then I performed the macOS upgrade. The upgrade was flawless through the usb boot installer. The system was snappy even without the post-install updates. I performed the post-install updates. The result was a fully usable system with no noticeable flaws. Watch unlock, hand-off and other features work. This system was upgraded to max CPU, Nvidia 2Gb GPU, SSC, 20 Gb memory, ac Wifi card and 4.0 Bluetooth. The performance of this machine is similar to the 2012 iMac.
Mid 2007 iMac 20" - Good Success. I had been using Mojave (DosDude Patcher) on this system for a long time. I recently upgraded the OS to Catalina (DosDude Patcher) with success. I decided to test Big Sur. I had a lot of trouble installing. The install would automatically circle back to the Big Sur install window. I used OCLP 0.2.5. 0.2.4 stalled in during the initial install process - freezing at the KernelDebug stage. 0.2.5 got passed that point and finished the install. To get around the circle-back annoyance, once each step was complete, I had to turn off the machine and turn it back on, pressing the OPTION/ALT key and selecting the USB installer. The system would complete each step, then I would have to turn off and back on with the OPTION key. I had to continue this until I got a Big Sur HDD boot drive, which I then chose. The system started in Big Sur. At first, the performance was devastatingly slow. I had to be patient as I slowly went through each install window. (frustrating). But once in, I updated the EFI with OCLP 0.2.5 and performed the post-install updates. BOOM! The system was very usable. Hand-off, watch unlock and other features worked flawlessly. Only problem was the graphic transparency has problems. As you move the Mouse in transparent areas, the colors change. I fixed this by reducing transparency in Accessibility settings. Big Sur isn't perfect on the iMac 2007, but usable and in some ways better than Mojave. The process with Monterey/OCLP 0.3.0 was identical with similar performance. The justification for doing this is being able to use the most recent Apple iWorks software which is very functional with this configuration. This system was upgraded to its maximum CPU, 6 Gb memory, SSD and upgraded ac/Bluetooth 4.0 AirCard.
