Copy Formula Down If Criteria Match

I need to copy down formulas from Row 4 to all rows below til end if value Col F > 0.

All other data on subsequent rows must remain intact.
Need to loop through all shts in the wb

Guess where I'm stuck, I'm not sure how to setup the destination range for the paste

Here's where I'm at so far
Just a snippet, not complete:

Sub Evaluate_Paste_Formulas()

Dim wbBook As Workbook
Dim sht As Worksheet
Dim rngCopy As Range
Dim rngDestination
Dim lngRows As Long