I doubt any PH in Zim (or any African country in fact) would complain if you wanted to use a 9.3 Double on Elephant. But be warned, its when you follow them into the thick cover that they use as a refuge. Or when the other Elephant want to extract revenge over a fallen family member that will have you wishing for something bigger.

A Tuskless hunt later in the season would be my recommendation due to the leaves falling of the trees thus providing more visibility. Early season can be mighty thick with bad visibility and obscure shooting lanes.