Calculate Linux - Gentoo GPT Partition Table and how to make a Bios Boot Partition with Gparted.
This will of course work for all other Linux distros.
If you want to circumvent the limitation form a MSDOS Partition table with a max of 7 useful partitions, GPT Partition Table is the answer.
Lots of people surrender, latest, when the soon to be installed distro is asking for a bios-Boot-Partition and Gparted doesn't seem to have that option.
It is no rocket science, just watch the video and enjoy.
If I only helped 1 person with that video, then I can say job well done.