I don't know what Accord you're driving, but mine makes its peak power at 5800RPM (150 horsepower.) However, dyno charts for parts I've bought (AEM CAI, DC Header) show peak power being produced up until 6300 (redline, fuel cut off is 6500).

I've got a slipping transmission already, not horrible but when I leave in 15 minutes for the day, it'll slip a few times till it warms up. More than likely it's my own fault.

I don't know about letting off the gas to simulate a clutch, but I've got an AT and this is how I've raced:

1. From a stop, on the line, throw in N.
2. Rev to about 3-4K, depress brake as hard as possible while revving
3. Release gas pedal (stopping rev in N), keep brake held down as far as possible
4. Put in D3 or 1 (Whereever you feel comfortable starting)
5. When brake still depressed from revving in N, rev motor to maximum revs without letting the car move forward (For me it's about 3K)
6. When the light turns green (I'm talking drag lights, not stop lights ) release brake + push in gas as hard as possible

As far as shifting, I just shift right before fuel cut off without using the brake at all (not simulating a clutch?)

If you're going to downshift (suppose you're going 50, and you punch it, it'll drop to 2nd gear) I'd punch it, let it shift, drop gear shifter into whatever gear it's currently in and wind it out

i.e.
1. Going 50MPH (WOOHOO!!)
2. Punch it, it drops to 2nd gear
3. Put shifter in 2nd (ECU says max gear now = 2nd, instead of downshifting manually)
4. Upshift at around 6300/71MPH (We ARE on the interstate, RIGHT? )

Like I said, I don't know what you're driving but the basic boltons will improve performance, a turbo kit, nawzzz, et cetera. If you're going to be doing this a lot, a transmission cooler might be a recommended upgrade.

Hope this helps!