Aptos preset font size in new installations

You are comparing first-run compose defaults across four Outlook clients and want to know whether 12-point Aptos is Microsoft's universal standard. These clients do not share one documented default-font profile. Microsoft support guidance explicitly identifies 11 point as the initial size to restore in classic Outlook, while new Outlook guidance only explains where a user chooses font and size; it does not declare 12 point as a cross-client standard. Your observations are consistent with client-specific defaults, but they do not prove an official tenant-wide value. For a clean validation, create a fresh test profile, confirm no roaming or migrated settings, and inspect Settings > Mail > Compose and reply on each client. If your organization requires consistency, document the desired size and configure it separately in every supported client. Treat 11 point as documented for classic Outlook and 12 point as observed, not officially universal.