Stick to the book
Look, believe the oTd, you just do not try a three-engined ferry in a four holer. We did it once out of a desolate African airfield, it was terrifying. Terrifying. (no pax and essential crew only, daylight, good VMC etc, all in the book).
We also did some training on three-engined take-offs afterwards, as a result. Further result : even more terror AND a burst tyre. Much embarrassment too.
You may save fuel if you can safely close down a donk when you are holding, maybe, but just consult the FOM and it will tell you everything. Best not to try non-SOP stuff I reckon, don’t be clever, just be compliant. It’s much safer.
And if you do things which are not in the book, well, what must I say ? You are an idiot.
The operational Take-off dude, well, used to be.
oTd