‘Normally, a kebab spit is grilled vertically (on edge) so that the outermost, cooked-through layer can be easily cut off with a knife.
The spit in the mini oven runs horizontally (lying down). It is important that the weight is evenly distributed on the spit so that it can turn evenly.
If you grill a kebab/gyros spit in it, it could have an unfavourable effect if something is cut off again and again. This changes the balance and the spit may no longer turn evenly. It may also be difficult to cut off the outer layer evenly with a knife in this horizontal position.
But as with so many things, only trial and error will tell you how you get on with it.