Pico de Orizaba-the route

what we will do is go up to 3500 m today....put up camp and go for a day hike....
then tomorrow we go up to 4200m and sleep in Pietra grande (in a hut...where it is supposed to already be really really cold)
and on day 3 we will attempt to summit to 5760m in the nighttime and with temperatures as low as -15 degrees C without wind....with wind it will be much much colder....