Brandilion, it really depends on what you would prefer to use. I would stick with a snaffle unless both horses neck rein well. I will usually move a horse up when they are pretty consistent at neck reining and only occasionally need a bit of correction.
If you are interested in the bit that I use, this one is almost identical (the company that made mine doesn't make them anymore). Pinchless Low Port Reining Bit - Statelinetack.com