What are you running --- manual or auto?
Are you running straight through the waterbox or are you getting completely around it?
Since (I assume) you are on street tires, don't even go near the water! But, b4 you get to the starting line, spin your tires over a bit (very small burnout--- not really a burnout b/c you really don't wanna heat up the tires much at all-- just enough to clean off all the leftover rubber and dirt on the track from other cars' slicks and/or drag radials). You shouldn't be spinning out to the 60 ft mark. THat is just a waste of time and gas. It is likely you are running through the waterbox (maybe not... i dunno, but likely). If possible, get yourself some Nitto Drag radials (NT-555R). Those are the best drag radials to drive on the street with good wet traction (get the BFGs if you want a better dragstrip radial at the cost of less street traction and less street life). You'll feel a BIG diff with the Nitto DRs than on street tires.
If I were working at it, I wouldn't focus too much right now on reaction time (for reason already stated by
Dark Knight). Work on getting up to the starting line with clean, dry tires and getting a great launch. Also, stage as shallow as possible (when the first light on the tree comes on as you roll forward, creep a LITTLE until exactly when the second light comes on and STOP). You have about 5-7 inches until that second light goes off, but you don't wanna use that extra room.