PerfectIt Cloud includes the option to use all of PerfectIt's built-in styles. So you can check UK, US, Australian and Canadian spelling as well as United Nations, European Union, World Health Organization, Government Publishing Office, American Legal Style and Australian Government Style. However, it's not possible to customize it for your own house style yet.
Our plan for customizing styles is to make all of the options in PerfectIt possible in the longer term. However, the technical work to make that possible is more complicated than it sounds. So our goal is to do that in the following stages: