Availability of Belize Plus Theme in SAP Cloud Platform Theme Designer

We'd like to utilize SAP Belize Plus as the Base Theme for our custom Theme in our Portal. However, at the moment it seems as if SAP Belize is available when creating a new Theme in UI Theme Designer, but SAP Belize Plus is not.

Are there plans to allow SAP Belize Plus to be available as a Base Theme? I've tried to adjust the settings to approximate SAP Belize Plus in my custom theme, but we cannot get the settings right.