Others know more, but I'd keep it in D.
Sometimes I shift into OD after going through the traps.
The 1-2 shift happens so fast that you should probably let the tranny shift itself. You could shift 2-3 manually if you want more revs and have a tach - or a good ear/feel and some luck.
In other words the optimum rpm to cross the line is at peak hp. The stock cam is done by 5000 rpm, so if you go a higher mph you need a taller tire to bring the rpms down. If your cam is done at 5500 you can go faster for a given tire size/rear ratio than the stock cam.
These numbers are for illustration purposes only, and assume good valve train components.
If you dyno your car then you will know your peak rpm, then do the math and some runs.