For fastest reads/writes, you want OS in first partition on HD, installed with other HD"s unplugged.

Preferred HD booted via BIOS boot order priority, other OS HD's booted by one-time BIOS BOot menu.

Any installs/repairs are done with all other HD's unplugged to avoid derailng the boot files to a preceding Active partition.

Logicals are only used for Data, and mainly only needed when you already have 3 Primary partitions on the HD since you can make as many adjacent Logicals as you want.