Issue: Setting the initial "Default Mode for Watching Wiki Content" ?

In the Xenforo version of VaultWiki it is possible to for a user to set their own default notification preference for watched wiki pages, which is fine. How/where would I go about setting an initial option for this for users who haven't configured their own default? VaultWiki: Notification admincp settings seems like where I would find an option to set this, if it were available.

The initial default mode for my admin account was automatically set to "Alert and instant email notifications" which is no big deal for me personally, but my concern is with potentially hundreds of users (or thousands one day?) watching various wiki pages, they might not appreciate a stream of emails coming in unless they explicitly choose email notifications themselves. I fear many of my users won't bother or realise they can set a default notification option & also won't scroll down past the submit buttons on a wiki page edit screen to set the notification option for that page.

As a separate question, is there any flood control on instant email notifications? For example, if a watched wiki article receives 5 edits in 20 minutes will a subscribed user receive 5 separate emails?