Separate the 8 eggs, placing all the whites in a large bowl and placing 4 yolks each in two small bowls. Set 1 bowl of yolks aside for the custard.
Add vanilla and coconut extracts to remaining bowl of yolks and whisk together. Set aside. In another bowl, whisk together the flour and salt until airy and free of lumps. (You can also use a sifter.) Set aside.
With a mixer, beat together egg whites and cream of tartar on medium speed until frothy, then slowly begin adding the sugar, a spoonful at a time. Increase the speed and beat until the whites hold a soft peak when beaters are lifted. With a spatula, fold the egg yolks into the whites, then fold in the flour, scraping and lifting from the bottom of the bowl, being careful to deflate the whites as little as possible, until no streaks of dry flour remain.
Divide batter among the 2 pans. Bake for 28 to 30 minutes, or until cake springs back when pressed gently in the center.
Place pans on wire rack to cool completely. The cakes will shrink a bit as they cool.
While oven still is hot, spread coconut on a rimmed pan and toast until golden, watching carefully and stirring occasionally. This will take about 5 minutes for chips, 10 to 15 minutes for flakes. Pour toasted coconut into a bowl and set aside.