Install confusion with UEFI MATE (SOLVED)

Hi all,
Long-time Sabayon user here. I’ve been testing Calculate on an old secondary laptop for awhile. I don’t recall any issues with the legacy 06.2017 install. I like it a lot and hear comments from reviewers that it’s the closest to Gentoo of the derived distros. So i decided to make Calculate my main distro. When i try to install the 12.2017 MATE in UEFI mode with manual partitioning i am having problems. I want a small efi/boot partition, a generous /, and a bigger /home. I set this up with the included gparted and start install. I select to keep existing partitions but it will not install that way. If i select Auto it tells me i cannot change anything. Eventually i installed as legacy auto. It works ok, but it has created a swap partition i don’t feel i need, and put Home under something like /var/calculate/? Can someone explain to me how to make the install as i want, or point me to an English youtube vid? I’ve watched the French and Spanish versions but i am far from fluent and apparently miss too many key steps. Many thanks!

I select to keep existing partitions but it will not install that way

Why this option is not suitable?

When i switch from the default selection of autopartitioning to keep existing partitions, it appears i must also collapse the options below these fields. Otherwise, even if i don’t make any changes, the installer considers i am trying to do make changes. Once i collapse these fields i am able to proceed. On the next screen i then choose my root and home partitions which i have created previously, leaving the first partition alone as it is already “taken” as efi/boot. Not exactly intuitive, but hey they did say this was the closest distro to Gentoo… Now happily using Calculate as my main os and set up the way i want.