Calibrate recommends: Custom Plan (Odoo SH)
The Standard Plan includes access to all standard Odoo Applications but does not allow for any customisations. Its is hosted by Odoo on a shared server.
The Custom Plan (Online) contains all Odoo Applications, Odoo Studio, Multi-Company and basic automation functionality. It is hosted by Odoo on a shared server.
The Custom Plan (Odoo SH) contains all of the functionality of the Custom Plan (Online) but is hosted by Odoo on a dedicated server. It allows for the installation of Third Party applications and other hardcoded customisations.