One thing not mentioned so far is the direction of ditching. Over the years there has been quite a bit of debate, especially about ditching smaller aircraft. One side had it that in any noticeable sea state one should ditch along the direction of the waves (swell) to avoid catching a wave top and going nose down into the next one. Certainly when I owned a seaplane in the early 2000s we were concerned that you could hit a wave top, get thrown back into the air at less than flying speed and stall into the sea nose first. Some thought that a smooth entry along a wave top might be better though I don't think the debate was ever settled.