Hi, the ability to show widgets on individual pages is already built into Gantry, no additional plugins are required. This is possible through the override system, not only can you have different widgets on any page, you can have completely different layouts, styles, ECT. Anything in the theme settings and widgets can be assigned on a per page basis.
Oh, I know abou the overrides. The plugin was really useful for me because a lot the same subject information is going to be used on different pages (building a corporate site, not a blog). With the plugin, I could create a widget and just click a check box to show it on pages a, c, & f. WIth the overrides, I have to create override pages for a, c, & f with all the same widgets on them since not all pages will have the exact same content but much is repeated.
If there is an easier way, by all means, let me know. But as of now, I expect to have at least 30 override pages.
How you have to do it is completely dependent on the situation. If you've got 3 pages that have the same set of widgets, you can just create one override and assign those three pages to the same override - you don't need 3 separate overrides. The assignments are key in overrides, if you get creative you can cut down the number of them.
As an example: Say you have a set of pages that need specific widgets in the sidebar only, or the sidebar moves to the other side for those pages, you could just create a "sidebar" override that has those changes and assign the pages that need that layout. Also keep in mind that pages can be assigned to more than one override - just as long you're not trying to override the same settings or positions in both overrides - they need to have unique settings that don't conflict with each other. You could have a "sidebar" override, a "feature" override ECT - and just set the widgets in those positions and assign the necessary pages. Point here is that you don't always have to do it one page at a time, there are ways to consolidate and simplify. Of course, if you have a page that is completely unique to the others, it will need it's own override.
All you need to do is plan it out a bit to find what is going to work for you. There is always a way, Gantry is extremely flexible, it just works a bit differently than other WP systems.
The difficult we do immediately, the impossible takes a little longer.