OS X :: Script To Duplicate Apple Lossless ITunes Library As MP3 Files?

I have written the applescript below to duplicate my Apple Lossless iTunes library as a MP3 Library. I wanted the script to be able to do the following things:

1. For all Apple Lossless tracks in iTunes Library (at the moment the script is just set to work with a selection for testing purposes) check if track already exists in MP3 folder with more recent modification date and:

a If yes, do nothing

b If same track with earlier modification date convert and replace track (so that tag changes are transferred)

c If track doesn't exist convert track.

2. If there are any MP3 files in the target folder that aren't in the source folder (i.e. the iTunes Music Folder), delete these files. This is for the scenario when I delete files from my iTunes Library that I no longer want, and I want the equivalent MP3 file to be deleted as well. So once the script has finished running there should be an exact match between the Apple Lossless library and the MP3 folder.

The script below does everything I want it to do with the following caveats:

1. I am not sure how to go about deleting the MP3 files as in part 2. I guess it would have to be an additional section of script which compares each file by name in the folder/subfolder in the iTunes Music Library with the equivalent folders in the target music folder, deleting any files found in the target music folder that don't exist in the iTunes Music folders, but I'm not sure if this is the best/only method, and how I would go about scripting this.

2. Because I need to specify the conversion twice (once if no file exists in target folder and once if it does but with an older modification date) I am wondering about using a subroutine method here. I tried doing so, but no conversions happened even though some should have happened. I wonder if this is because the relevant variables aren't picked up properly by the script when it's a subroutine. I can leave things as they are, just thought it would be good to make the script neater.