Don't change your deadlift technique in this program. Ramping to records in 2 weeks requires that you already have a significant amount of experience and are conditioned to perform a given lift. So in reality, if you wanted to pull conventional, you needed to have been doing it for a while before this 4 week block. Although I prefer conventional for functional strength, athletics, and general developement - it's not like there is a big enough gap to stress over here. Sumo will do you fine.