One of my many previous company's had a rather good system I think. We had a very simple table which had aircraft weight on the left and 2eng and 1 eng initial deck angle in colums on the right. Both of these deck angles were written on the bug card for every departure. At Vr, the call would be (for eg) "Rotate 13" meaning rotate to 13 degrees. After a couple of seconds the F/Ds would invariably settle down at 13 degs. In the event of an engine failure > V1 the call would be (eg) "Rotate 10, Engine failure" though personally I found it easier to look out of the window provided there was a decent visual horizon.