Neatline Exhibit Zoom Control Setup

How is the widget zoom range controlled, for a given exhibit? I am using a World File (.wld) to define coordinate space of my vintage map, and have a default background image the same dimension as the map. The default view is nice (the slider full "-") but if the slider is moved even 45% to the "+" end, it is way too magnified.
What is the proper procedure for setting this?
http://industrial-history.org/archive/neatline/show/map-of-greenfield-mass-1884

ZoomLevels are controlled by the OpenLayers JavaScript library. Neatline relies on the WMS request specification to calculate the numZoomLevels in the map view (see http://trac.osgeo.org/openlayers/wiki/SettingZoomLevels), usually adding about 15 - 18 zoom layers. The Neatline 2.x uses Backbone.Marionette to allow developers to inject "new" functionality in to the plugin to make it more modular. This is actually how the Waypoints and Simile widgets are constructed. This would be the way we would suggest modifying the default behavior.

That said, so long as the author of the exhibit is a bit careful in setting the zoomLevel for a particular item, this doesn't particularly pose an issue for the user experience.

HTH,
Wayne