well the official is out in the App Store, I run the OLDEST board on here probably, Gigabyte EP45-UD3P quad core 9550 clover spoofed to a late 2013 iMac 14,2 - running high Sierra, currently with non efi clover, I am currently making the install usb just fine, even with the non support error, to do so do. this,
make a usb disk normal mac way , 1 partition/guid, journalized then name it USB copy paste this line in terminal , type admin pw and wait
sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/USB --applicationpath /Applications/Install\ macOS\ Mojave.app --nointeraction
if your at least el capital or better you will get a message like this below.,.. but just wait, it WILL MOVE, just slower, then copy the utilize you need also to the disk, like clover configurator, clover boatloader etc, then run clover and choose the USB as target to make it hack bootable, then rock on. install as normal, CCC your drive before upgrading so you have a fallback option, if my old a$s board can do this, your newer ones definitely can
WARNING: "--applicationpath" is deprecated in macOS 10.14 and greater. Please remove it from your invocation.
Erasing disk: 0%... 10%... 20%... 30%... 100%
Copying to disk: 0%... 10%... 20%...