ORIGINAL: vertical grimmace
I would start with zero. You can always add it if needed. Generally fully symmetrical models are set up 0-0-0. One question, why the NACA 0012? It will be hard to slow down, have a relatively high stall speed, and be fast. If you keep the weight down and the area up, probably no problem. Just keep these things in mind.
The rather blunt leading edge of the NACA 00xx series gives them fairly gentle stall characteristics.
I've built probably 50+ planes over the years that had 00xx's ranging from the 0012 to 0023 and all were outstanding performers with mushy rather than violent stalls.
The 00xx's are my "go-to" airfoil when I design some new aerobatic plane from scratch. When you've got stump puller grunt to drag it around, the 0023 is incredible characteristics.
As an aside, Howard Rush's famous Nemesis II C/L combat plane used a 0012, as did its fully elliptical cousin Bob Burch's Bosta. Both set new standards for performance when they debuted.