I'd start with an ackie over a savannah if I could redo it. Ackies are smaller, require less space, and are generally not aggressive like so many savs tend to be. By the time the sav hits 2-3', the bit will literally bring tears to your eyes just from the pain, not to mention the thrashing they do once they bite. That was the last bite I ever got that made me clinch my teeth and run for my vodka. Unless you have lots of time to spend on cleaning, feeding, and taming, I'd say avoid a sav at all costs. A tame savannah is hard to find, a tame or atleast non aggressive ackie is a lot more common. You do the research.
Just be aware that a savannah will need a min of a 6' by 3' cage to do it right, an 8' by 4' is what I would go for if I did it again.