22-25 inches, in general it should be fine as it comes from the factory. I would not shorten it.
Personal preference though, just make sure you do not negatively affect the balance of the rifle.
For me too much emphasis is put on "swinging ability", pointability etc. 99.9% of the time you as a client will be shooting off of shooting sticks or some form of rest and this is not a bird gun after all.
Rather stick to a rifle that fits you and is balanced and that you are comfortable with.
Shorter barrels lesson powder burning time(especially in a magnum) which may affect ammo performance. Depending on how much you shorten the barrel, muzzle flip may increase which in turn increases recovery time on your second shot. Muzzle blast will also increase with a shorter barrel, all in reason though.
Again anything between 22-25 inches will work fine and if you are happy with it go for it, I cannot see any real advantage of a 22 inch barrel vs 24 inch. You ain't going to shoot faster or better or be more comfortable carrying a 22 inch vs a 24 inch for all practical purposes in Africa, the difference is just too small.
Go with what you personally prefer.