In lu of my last post.

Well as for the rep hold routine. This is not so much for cutting, but rather shear muscle stamina and strength building.
Think about this for instance:
The longer you hold something, the harder it becomes, yes? Just like the part in the movie Punisher, when the evil son of the bad boss is told to hold a mine in his hand. The mine only weighting about 7 lbs, although over a prolonged period of time becomes seemingly more heavy. Hence he eventually drops the weight in his efforts to stay alive.

Something else to try:
Look at stamina core training. This makes the most sense to me. I don't care how many sit-ups I can do, rather how long I can hold a sustained position. I do what in the exercise fitness world calls a plank.
Plank: Core training routine where the user sustains a position much like a push-up for 30-60 seconds.
However a modified positions using either weight or a Swiss ball to preform a harder variation of this routine.

Planks are by far, not over rated, rather overlooked. I see so many gym users who don't try these its insane. Guaranteed core strength in about 2 weeks from doing these. You may not get your six pack this way, however you will get plenty of strength.
Which do you prefer?
Colby