The ol' fried green tomato pie dilemma
First, tomatillos are NOT used in this recipe - they are in the tomato family, but that's where it stops. Use green tomatoes which are unripe red tomatoes. So to say unripe green tomato just doesn't work.
I use equal parts flour and cornmeal (sometimes just one of them) then I season fairly well with salt, pepper, garlic powder (not too heavy), and ground cayenne/red pepper (sometimes, not always). I have been known to put a little cornstarch in the mix too and one time I even used pancake mix 'cause I was out of flour! Tempura batter will also work.
Dip in order - Flour mixture, egg (sometimes I put hot sauce in my egg mixture too), flour mixture - fry. Turn only once.
And follow Katie E's lead about the wire rack - this will let them drip dry versus one side getting soggy on a paper towel! That is good advice and something I haven't always done. Also, if you don't heavily salt your flour, as soon as you put them on the wire rack to cool, sprinkle with kosher salt or gray salt - the gray salt is a great textural thing.