I found that even in the dark, the white water was quite visible, though, quite honestly, 90% of the steering was done by feel, after the first few hours. The stern would lift as the waves approached and I would set her to race across the face, much as a surfer would, then as the whitewater caught up with us it was necessary to put her stern directly into the approaching water (which I could certainly hear, if not see) and slow the boat and let the wave pass under us. Though the noise was terrible, I welcomed the dark, because seeing those waves was a truly terrifying site at times.
With respect, you're either very brave, have really low survival instinct or have a real slow boat. At between 7 and 9 knots downwind with a 30ft following sea, I don't need white water to get my boat surfing - the boat takes off. And when there is no white water, you don't have any idea when that is going to happen. Until you're doing 15 knots into the trough. No thanks, not for me.
I don't know if you've ever had a huge wave mount a boat in heavy weather, but for me the boat became completely unmanageable with several (hundred?) tons of water washing over the stern and filling the cockpit. It doesn't matter how big your cockpit drains are, they are never large enough to rid the boat of the extra weight quickly enough to allow her to rise for the next wave.
Score 1 for centre cockpit. Oh and a cockpit is generally not more than about 4 cubic metres in volume which is less than 4 tons. And if my cockpit drains can't cope with that then in New Zealand I would not get a Cat 1 cruising clearance - they wouldn't let me leave.
I agree with some others - going to sea without some form of slowing the boat is very risky - storms can last for days and unless you have another very clever/good helmsman aboard, you can't take that sort of punishment for days on your own. If I asked my wife to "surf the boat along the wave and then turn it down just before the white water hits", I'd get a huge middle finger - nothing more.