I'm designing a web application with multiple modules, and am using floating sidebars for new event creation. Currently, the sidebars have different widths since the number of form fields is significantly more than that of the other. Is it ok to have sidebars of different widths under different units of a single application or does this make the experience inconsistent?
It will make it inconsistent, but I doubt it's worth worrying about.
It sounds like you'll negatively impact the user experience more by keeping them the same size.
If you look at any major commerce sites like Amazon, you'll see that they'll use a variety of layouts and column widths. If a user is capable of navigating sites such as these without this becoming a problem, I don't see floating sidebars of differing widths being a problem either.