Worth watching the flaps too. Speedbrake with flap really shakes the flaps something horrible. I find it a little dismaying many pilots regard speedbrakes as a natural way to slow down everytime, rather than applying energy management. I've even caught some intentionally keeping higher altitude/speed in a circuit so that when it came time to descend/slow, they can whack out full speedbrake. It seems to escape them that speedbrakes are very good vibration devices and not very good slow-up devices!
The 747 doesn't take much longer than a 737NG in the deceleration phase. Flap to 5 takes longer, but the descent planning and slow-up phase is almost similar.