I will use two stroke techniques during the EC - both tall, flat and with side rotation.
Modern freestyle swimming has evolved to a hip-driven stroke, which is identifiable by a catch-up and glide at the top of the rotation providing maximum core engagement and power. For long distances, it is accompanied by a two-beat kick to stabilise the body; for middle-distance to long distances, a strong accompanying six-beat kick can drive propulsion but at a cost : the glutes are the body's largest muscles and use an enormous amount of oxygen when engaged. Ian Thorpe, the GOAT before Phelps, nearly touched his fingers on the glide. I watched Matt Biondi crossing 25-yards with seven rotations.
Alternatively, a shoulder-led stroke has a faster turn-over and less core power with an early, hard 'hook' a the top without a gliding pause. The legs can be awkward and often do not play a role or a two-beat cross-over to keep the body centred. I think of Janet Evans, whose 'windmill' broke world records in the 400, 800 and 1500m in the late 1980s.
Depending on the event, hip-led and shoulder-led can be used together on opposite arms, creating a powerful "loping" effect - Katie Ledecky is the only woman I have seen do this.
Some data : when I use a hip-driven technique I complete 100m with 72 strokes. When shoulder-driven, it is over 90. Shoulder driven, for me, is more taxing but also c 5% faster (my guess).
So, that out of the way, adapting to the Channel conditions will play its part - if the water is calm, the hip-led stroke offers greater efficiency; choppy waters and it is the shoulder-led stroke allowing more adaptability to the waves.
Finally, I am able to breath on both sides which will allow me to swim either side of the boat, useful depending on the direction of the winds and therefore the chop.
Here I am using the hip-led freestyle at the catch-up or top of the stroke :
.