CentOS-7 installation on two disks (SSD + HDD)

I am trying to install CentOS-7(GNOME) on my Dell Laptop which has 30GB SSD and 1TB HDD, RAM of 8GB, i7 Intel processor. I am doing manual partition. I have selected SSD as bootable drive and my /boot is on SSD with 2GB as size. In which drive should I put the leftover(28 GB) SSD for better OS performance? I tried adding it to / but this is only allowing me if I deselect HDD. But then I am not able to add other partitions like /home, swap, /usr, /opt, /var on HDD and they would all default to SSD which has only 30GB in total which I am trying to avoid. I am planning to use this laptop for my development activities eg Java(with Intellij), Docker, Kubernetes, MongoDB, Apache Flink which at times would be resource consuming and I want to utilize SSD as much as feasible. Does the CentOS installation always default to the disk with higher space? Should I simply install to SSD(deselect HDD) and then after installation mount other partitions on HDD? So far, I am trying to follow instructions here : I'll appreciate if someone could help.