How much depth do dive bombs add?

[landingzone]

Does anyone have a good feel for how much depth is added to various coppers with various dive bombs?  Also, where along the length of the copper are they most effective.  ie. can I make a 450 copper into effectively 600 copper performance?  , or a 300 act like a 450?

[zackblain]

I think it's 8' per ounce