But I still don't understand why you want to select a certain amount of files from a list.
I'm making the assumption that the first set of file entries in the layout.ini file are needed for boot-up. The next set of entries are those used for loading start-up programs. Then next set of entries are applications I use regularly.
I would like to place all those entries at the beginning of the disk since they would significantly improve system responsiveness.
The last set of entries are programs I use occasionally so I don't need them in that zone.
In any case, I've managed to make a robust system disk script
that seems to do well enough even without this feature.
So if this feature is difficult to implement then don't worry about it.