Do this....
Take your default gunsight and copy it to a new name, like htcdefault.
Now, double click on the default gunsight file, the paint program will start. Zoom the picture out to 800% and turn on the grid lines.
Place a blob one pixal up from the bottom on the centerline. This is pretty close to where the bomb site needs to be. Put this blob on your target and drop your bombs.
Now, place another blob halfway between the bomb site and the gun site. This is pretty close to where the rocket site needs to be. Put this blob on your target and shoot your rockets.
A 45 degree dive works well. So does a 30, 71, 43, 57, 64, 83 or even a 90. Just get the feel of it, by practicing.
Try to hold the sight steady on the target for at least 2 seconds before releasing the weapon. Accuracy improves the closer you are to the target.
The German rockets fly a little different, use the gun site to aim them.
Fine tune your sight by using the attack you prefer.
If you can't figure this out, let me know I can send you a sight to start out with.
Good luck!