While in Reader View, simply open Browser Settings to reveal a new option labeled, "Text Size" (shown below.)
Text resizing in Reader View is a step in the right direction toward our upcoming goal of supporting Dynamic Type across the app.
One might wonder why Text Resizing is not available in WOL's web browser as it is in Safari. This is due to limitations of WKWebView (the in-app browser provided to developers on iOS.) We'll continue to revisit this capability following future iOS updates.