Custom fields in Request Forms

Here are a couple things I have noticed about forms and custom fields..  With the exception of the text field, you can only match to a custom field of the same type.  So a number field in the form can only match to number custom fields, etc. 

For single and multi selects, it seems to only match up to the custom field if you use that custom field as the options.  So choose the 'Use custom field as options' option.

Hopefully this helps a little.  It would be nice if Wrike had a more detailed docs about the idiosyncrasies of custom fields in forms.