A lot of a people are confused by gears. The rear gear only gets you into the power band more quickly. Getting off the line is the most critical point of drag racing. Every mph you add at the beginning of the track is one you get to carry through its entire length. Going to numerically higher, aka "shorter," gears will always help you come out of the hole, as long as you have the traction to make use of them. The optimum rear gear ratio will be the one that takes you through the traps at, or slightly above, the shift point in your final gear, assuming you can keep it in that final gear. This will give you the highest power "under the curve" throughout the run.
The only way a shorter gear will cost you, all other things equal, is if you end up being forced to shift into a gear that takes you out of the powerband, or you're forced into a gear you can't take full advantage of, like when you would cross the traps in the 1/8 at the top of 3rd, but now with a shorter gear you have to shift to 4th with like 200 ft to go.