RB Bombing - stationary targets

All you need to do is slow down during descend. Then if you have slow speed about 200-400kmh (depending on your aircraft) and you are heading towards ground, then you
can use flaps to ensure you will be able to get the nose up just after the bombs are realeased.

At altitude 638m I tried to get the nose a bit up. I am aiming and at 615m I am ready to drop the bombs. The pillbox is bellow the yellow circle because the bomb will fall down towards ground because of gravity. If you would have shallow angle, then you would need to get the nose up yet a bit more. My angle was -27° during aiming (at this moment pillbox is just above yellow line). -27.5° when the yellow line intersects the pillbox. Then at 474m altitude the pillbox is not visible, it is hidden under the nose. This is good distance because my aircraft is not in steep angle bigger than -30°. The ideal angle of the nose would be -35-45° then the pillbox should be somewhere just above the yellow line. So at this point I am dropping the bombs.

In this night map I have dropped the bombs at altitude

Here the bunker is too above the yellow line - need to be under it or over it depending on the angel of descend.

Here you see the estimate area of hit. The bombs should bounce so I think the pillbox was hit 100%. The bomb on right could damage the pillbox even if it would be 45-50kg (just a guess).