Climb gradient:
If you are asked in the sim or in reality if it happens to you, just look at your FPV.
Take the value you see, multiply it by two and subtract roughly 10%. Et voila.
For examle FPV 2.5° X 2 = 5- 10%= 4.5%
This way you can memorize some values for the all engine case and get a better feeling for the performance of your aircraftor, or be able to judge the performance when having an actual engine failure.
Regards
repulo