Yeah they split easily and straight. I use a machete and mallet, and split down the middle and leave them to dry. I doesn't take too long to dry, a couple weeks to a month.
After they are dry I split them further into sizable backing slats. I don't bother breaking off the partitions until they are split into slats.
It's really easy compared to the other aspects of bow making. You'll have it figured out in about 5 minutes