My baby dum went straight into a 3'x2'x17" cage complete with a perch and branches, he never went up. My bp uses the space more and occasionally climbs up there when he's hunting so moved the dum into a longer lower cage and the bp into that one. The dum is nonstop buried in the substrate or under a hide, he used to go in a cork log but is too big now.
My Dumeril was in 3,2x1,60x1,60 feet enclosure before when he was younger with no branches or perch. So as i moved him to his adult enclosure, i had the space to provide him with a tree branch to climb on. And he did not disappoint me at all.