ok ive had a bit of success with the bombing so ive decided to run throught a few of the things ive realised whilst playing...
first as you are getting used to the bombing start your bombing runs on a north to south or east to west track (or vise versa)
this way you get used to the wind effects a little easier until you are proficient at bombing.
Start your bomb run from a long way out.
I reduce speed to about half throttle and open doors early as this effects the speed due to drag.
Try to set your bomber directly at the target before you go to the site so theres minimal movement once you have calibrated.
In bombsite press the bombsite calibration key and bring up the clipboard and click on the base you are hitting.Make sure you click ACCURATELY on the base as the slightest deviation can set a completely different height.(zoom in on map for more accuracy)
now push up on the joystick and look for a hanger to track as near the centre line(your course flying) as you can. Here you will get an idea if you are right on course for the base or a little off target.
As you are so slow, if you are way off quickly go to pilot adjust course, go back to bombsite press calibration off and on again and move the joystick up to repeat the process of looking for a hanger to track.
Once you find a hanger try your best to smoothly track it for a few seconds whilst holding the MARK target key.
once you have done this you are calibrated.
NOW turn calibration OFF!
you will see that the bomb site now resembles the way it used to look in the easy bombing AH days

the crosshairs point in a sort of 45degree slope ahead of your aircraft.
Now bomb as normal (try not to swerve around too much to line up now

)
now whilst we are learning set a nice salvo.
i use .salvo 4 if a lone bomber with a .delay .3 so as to spread the bombs nicely.
if im in a formation i might use .salvo 3 or even .salvo 2 as the other bombers help cover a nice area and their blast helps kill the target.
if you really want to be sure then salvo all of your bombs with a .delay .5 (experiment to find the best timing) and drop just before your chosen target so your salvo (hopefully) covers a long track hitting ahead,on and past your chosen target.
hope this helps