When not too sure of the depth or sure there is not enough, I got used to a manual crash dive, which is basically order ahead flank and the requested depth. Doesn't take much longer than finding the C on the keyboard. As the main reason for crash diving is the sight of planes I also add a 15/20° rudder on one side to try to get off line of the bomb run. After that I usually pray because I can't do much more...
Of course you miss the scenic "Alaaarm !!" and the noise of the crew running all over the place, but well...