@kukris I think this is what you are looking for in the form of a registry entry imported during the install:
CODE
;change Recycle Bin info
[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\explorer\BitBucket]
"PurgeInfo"=hex:48,00,00,00,01,00,00,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,\
00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,\
0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,0a,00,04,00,00,00,00,00,68,4e,f5,\
bf
[HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Explorer]
"ShellState"=hex:1c,00,00,00,67,01,00,00,00,00,00,00,00,00,00,00,00,00,00,00,\
01,00,00,00,0a,00,00,00
Bonus: the HKLM entry reduces the size of the Bin to 4%. Make your changes to a test machine then consult these keys. You may have to reboot before the changes take effect.