I don't know about baroni, but my aurantiaca really don't climb all that much. If baroni are the same, the 36" isn't nearly as much of a factor as the footprint of the tank. I don't if that helps at all, but it's something to consider. I only put stuff in my tall tanks that are going to take advantage of all that height.
Mantellas do like a good climb. More floor space is important, but I think tank dimensions are best with some height, particularly with baroni, cowani, and nigricans. I rarely see madagascariensis climb.