Oh, look at me, I figured it out! For those curious,
I replaced:
Selection.AutoFill Destination:=Range("F2:F33") Range("F2:F33").Select
With this:
LastRow = Range("A1").End(xlDown).Row ' Ctrl+Down from cell A1 Range("F2").AutoFill Destination:=Range("F2:F" & LastRow) Range("F1").AutoFilter