shifting automatic

I have a 904 Torqueflight in my Duster and wanted to know if anyone had an idea of what rpm is best to shift manually. If I take off at a stop in "1" then i'll shift it into "2" shortly after then into "drive" which is "3". Does anyone know when exactly I should shift would be most effective. How does everyone else do it? Does it make a difference what all has been done to my 318. I have a 340 cam and edelbrock performer intake with 4-barrel if that helps. Thanks