You can find the source code repository here
https://bitbucket.org/resara/open-1-1
It contains the latest open1to1 code, except for some EFI work I haven't commited yet. In order to launch another script at boot time, you will need to modify the initrd. At some point I need to look into why the imager isn't working for you.
The open1to1 imager was designed to do one thing very quickly. However, it's fairly easy to modify it to do other things. For example, I created a modified version for use at Resara that would create and image raid arrays.