By middle number do you mean a "middle of the road" number from the "volumes of co2" range given? It gave yo 1.5 to 2.5,so it depends on if you want English carbonation (low),or American carbonation (high) to be general about it. Bottle English browns & bitters have higher vco2 than their casck versions as well. I'd go with 2.0 volumes to start with to get a middle of the road example of the style.
Everything works if ya let it-Roady(meatloaf)