live-usb-gui now offers choice of scripts to use, depending in your need you can either use live-fat-stick with vfat partitioned stick or live-grub-stick script which works with any partition format supported by grub2 including vfat, must be used if you have iso bigger than 4G.

live-grub-stick can now create bootable USB from openSUSE installation media isos (standard DVD or NET), difference from --isohybrid option is that the data already on the stick is not touched, the whole iso is available on the stick so you can use the stick to copy it around apart from being able to install from it.

Two new options --suse-persistent(for openSUSE live ISOs) and --ubuntu-persistent(for Ubuntu and clones) are now available, using these options allows live sessions to be persistent over multiple boots, even when used on vfat partition. Again the way it is used does not need change in partition format of the stick, existing data on the stick remains untouched.

Feel free to fork https://github.com/cyberorg/live-fat-stick if you want some more enhancements.