you get get the size and number of items currently in the recycle bin with this code

Hope it helps

Code:
' This code is licensed according To the terms And conditions listed here.

' Display the number of items In the Recycle Bin On the C:
' drive And the size of it.
Dim rbinfo As SHQUERYRBINFO  ' information about the bin
Dim retval As Long  ' return value

' Initialize the size of the structure.
rbinfo.cbSize = Len(rbinfo)
' Query the contents of C:'s Recycle Bin.
retval = SHQueryRecycleBin("C:\", rbinfo)  ' the path doesn't have To be the root path
' Display the number of items In the Recycle Bin, If the value is
' within Visual Basic's numeric display limits.
If (rbinfo.i64NumItems.LowPart And &H80000000) = &H80000000 Or rbinfo.i64NumItems.HighPart > 0 Then
  Debug.Print "Recycle Bin contains more than 2,147,483,647 items."
Else
  Debug.Print "Recycle Bin contains"; rbinfo.i64NumItems.LowPart; "items."
End If
' Likewise display the number of bytes the Recycle Bin is taking up.
If (rbinfo.i64Size.LowPart And &H80000000) = &H80000000 Or rbinfo.i64Size.HighPart > 0 Then
  Debug.Print "Recycle Bin consumes more than 2,147,483,647 bytes."
Else
  Debug.Print "Recycle Bin consumes"; rbinfo.i64Size.LowPart; "bytes."
End If
I will look for what you want in the registry