Vertical positions of the components can be set using 3 possible methods: relatively to a certain vertical position; relative to the font's ascender line and absolutely (relative to the base character's origin point).
Component characters may be identified by names or by their Unicode indexes using simple "uniXXXX" notation.
You can even define alternative composites! So if some of components do not exist in a font, Compo Compiler will try to make an alternative variant.
Compo Compiler properly copies kerning data from the base character of the composite (so you don't need to manually define new kerning pairs) and it can optionally generate Unicode indexes of the new composite characters using the FontLab database.
Compo Compiler comes as a self-extracting archive containing few files. Run it and enter the path to the FontLab (or TypeTool or ScanFont) directory as an extracting path. There is neither installer nor uninstaller for it - we decided to not increase the size of the downloadable file by adding features that are not really necessary, because Compo Compiler simply cannot work without FontLab or other products from the FontLab line.