Of all the plugins we use, the one that is heavily used is Quite Imposing Plus version 3. This is one is a must-have tool.
If you want imposition software, this one for the money is it.
One cool tool in Quite Imposing (QI) is masking. You can mask a certain area on one page or every page or odds or evens pages.
The latest version has a tiling feature which enables you to split a page into however many pieces you need.
This software uses a serial number and activation code to be operational so I'm not sure if this is worth uploading.