From the above replies, one thing is clear. No one sticks to the procedures recommended in the POH. Why not?
Surely one cannot do much better than lift off the ground at the recommended rotate speed for the weight - then select gear up as soon as positive rate of climb is noted. Avoid deliberately holding down in ground effect just to reach blue line. At night this could be positively dangerous as you are flying awfully close to the runway and could get a prop strike if the height mis-judged.
No point at all in leaving the gear down until you judge that you can no longer land ahead. Because unless you have a very long runway there is no way you can judge accurately how much you will need for what is going to be a single engine flapless landing at high speed maybe on a wet runway as well. Try it at night...
Anyway, the gear down theory to blue line only delays the airborne acceleration which puts the end of the runway that much closer.
Whether you keep your hands on the throttles, pitch controls or something more personal, doesn't really matter. You have to accept that in most light twins there will be a short period after lift-off when the aircraft is transitioning from gear down to gear up and where only superb flying skill will save the day ie airborne abort ahead or slow climb away.
A lot depends how quickly the engine failure is identified and the prop feathered. There is probably a 5-10 second critical period immediately after lift off where an engine failure could go either way.
Certainly I would avoid deliberately holding the aircraft on the ground past the POH recommended lift off speed. After all, if you hold it on the runway until blue line or beyond, and a failure occurs at rotation, you still have the gear dangling and the prop windmilling and you will lose speed very quickly indeed.
So what have you gained? An abort at blue line rotation may mean an over-run. Yet you cannot lift off and go, because you will never climb with everything hanging out at that moment and the speed bleeding.
Far better to stick to the correct POH procedure for take off and accept that there is a danger period of a couple of seconds which hopefully you will quickly accelerate past by adopting normal take off attitude.