For some reason OpenSUSE gave me a 25GB root logical volume, and left the other 150GB disk space unallocated. Partition Manager was happy to resize the volume while I was working on it. Thank you LVM.
opensuse progress: very nice guided partition setup, but was a bit taken aback about the text based WiFi setup prior to installation. Teaches me for trying the minimal install.
Had problems with software compatibility with Antergos so trying OpenSUSE tumbleweed now. RPM is a better supported format.