Or you could just use the factory OEM donut on the "front axle" to temporarily limp your VX to the nearest tire repair shop. What are the odd's of you actually having a flat with Nitto TG's with your style of driving (I'd say somewhere between slim & none)???
If you are dead-set on using a F/S spare, then any slightly smaller O.D. tire put on the "front axle" will be able to safely limp you to the nearest repair shop. The key is to never put the smaller O.D. tire on rear axle, and not be in 4WL when limping the VX to the shop.