I am no pilot, but if I were and if I ever had to ditch an aircraft, I would jettison the cargo, dump the fuel if possible, and land in the direction the waves were moving. I realize that having the wind at the tail would make for a higher speed relative to the water below than landing into the wind.
Having spent an unhealthy amount of time bashing various fast boats into waves from both directions, I can report that waves tend to travel at around half the wind speed. Hitting them badly from behind tended to result in much bigger crashes, purely because we were travelling roughly twice as fast, and therefore had four times as much kinetic energy.
If you apply a bit of vector addition to your ditching problem, it turns out that, because the wave is travelling around half wind speed, you're going to hit the
wave at roughly the same speed, regardless of whether you're landing into wind or downwind. However your speed relative to the
water is going to be a lot lower going into wind, so that's going to be the safer option.