I’ve been using command-line commands or the Clover Configurator to mount Clover’s EFI partition to edit Clover’s main configuration file.
However, I find it easiest to mount the hidden EFI volume in Disk Utility:
The hidden partitions will only be shown if Disk Utility’s debug mode has been enabled. In a shell, type:
defaults write com.apple.DiskUtility DUDebugMenuEnabled 1
Start Disk Utility and enable the option to show all partitions: