it would be helpful if you post what you've got as a gist, and we can try to work from there.
(it is possible, in the file browser menu to select multiple files, then send to gist from the wrench).
the trick to using custom views in pyui is that the class must be define before you use load_view, it is also possible that you need to pass the class of the view in via the bindings argument, though its been a while...
It is also possible to define custom classes that load pyui's directly. see
https://forum.omz-software.com/topic/3176/use-a-pyui-file-in-another-pyui-file/2
may be useful for how to deal with custom view classes that you want to load from a pyui file.