The "secret" to loading multiple tires in the back of the VX cargo area is to have them standing upright side-by-side in the "vertical" load condition. With the rear seat in normal upright position (not folded), you should be able to "vertically" carry 3 tires easily in the back cargo area side-by-side, with the 4th tire placed within the rear seat itself. Both front seats will remain empty for people.
& it's even mo betta to use small lightweight tires to decrease unsprung weight ... but in this case it'll be sprung weight ... never mind!!!