@michoel, in its open-source version, Salto wraps SDF (and knows how to workaround / properly handle various gotchas in SDF). As far as I know, there aren’t any known issues with Salto and custom forms.
In the commercial version (mostly the SaaS version, but can be used also from the open-source CLI), it is using a mixture of a SDF and a SuiteApp that we created in order to extend SDF’s functionality (to areas it doesn’t support today ; e.g. deleting files from the file cabinet, accessing the entire file-cabinet, working with
[user|company|accounting]Preferences
, etc.).