Ok I'll try and report back
I've installed the EFI for Comet Lake, removed unused kexts and added my USBports.kext
Also edited the plist replacing iMacPro1,1 by iMac20,2 and added board id, serial, MLB, ROM and UUID (couldn't find Smcplatform value so left the one that was there)
Now that I've done all this, what can I provide you with to check that everything is properly configured?
Thanks!