Formula in visible rows of filtered column

Good morning, Gurus.

I have applied 3 filters to a data set, and need to add a formula down one column of the filtered data. I know how to select the entire filtered range, but how would I select only a single column of a filter range, and then add a formula to the visible rows, (minus the headings in row 1)?

Here's what I've got that is NOT working:

Range("I1").AutoFilter Field:=9, Criteria1:="032961"
    Range("AA1").AutoFilter Field:=27, Criteria1:=">0", _
        Operator:=xlAnd
    Range("AD1").AutoFilter Field:=30, Criteria1:="0"
    Set Rng = Columns("AD:AD").AutoFilter.Range 'This is where I get the error
    Rng.Offset(1, 0).Resize(Rng.Rows.Count - 1, _
    Rng.Columns.Count).FormulaR1C1 = "=RC[-3]"
    ActiveSheet.AutoFilterMode = False

Thanks in advance for any help you can offer.

If this can't be done, perhaps I could use a helper column and just paste a formula all the way down the column. I still believe the earlier way would be neater.