if anyone does not know yet you can use the E6B for level bombing
just get your speed were you want it then open the E6B and play with your throttle till the speed gets steady and then Cal the bombsight and then just look at your E6B evernow and then to see if your speed picked up or slowed down
i was able to level bomb with a TBM at 6k within just half a sector to the base
and the bomb hit the mark dead on
happy bombing:)