Here is the best bomb delay conditions I've found out by experimentation:
*Large areas(HQ, large airbase, port, factories) - delay 0.6~0.7
*Medium areas(vehicle base, medium airbase, depot) - delay 0.4~0.5
*Small areas(FH, VH, BH, town) - delay 0.2~0.3
... This is the case of 1000lbs bombs. For smaller bombs(such as 20x50kg bombs on the Ju88A) subtract 0.1~0.2 from the delay listed above.
Targets like HQ and cities are ideal for carpet bombing, while some targets like ack factories have small number of buildings spread out in a large area and gains better results by JABO runs rather than carpet bombing.
As a general rule, bombing the largest area in a single pass is achieved by diagonal bomb runs against square targets by three buff formations:
