My partner and I are adding a new feature to our website, specifically one that allows a system administrator to email users of the system directly from an existing 'admin' screen. We are debating the most appropriate place to put the control, and wanted to reach out for opinion.
Here is a very rough mock-up of the current screen, with our two placement choices labelled A and B in green (note that by default all items in the checklist are selected and would have to be manually de-selected: One of us would like to place the button in position A, as it is above the fold for large result sets, more prominent, and saves the user having to scroll down to email the selected users. The other would like it in position B, as it matches other user interface buttons, and flows more naturally in that users Search -> Select -> Act and the top-to-bottom positioning follows this pattern. Users shouldn't have to search, scroll down, potentially select users, then have to scroll back up to trigger the email. The counter to this is that it is just as likely that a user searches and is happy with the 'select all' and hits the email button without de-selecting a user.
Is one of these options more correct in terms of UX and standards?