I would drop the 70mm TB, and if you didn't get the TA set on the dyno, I would put it on the rollers and get it set to make you the most power. Other than that you'll have continue to practice drivin' the thing to cut your times down....if you could put some drag radials on it you'd get a better 60' time and probably a better E.T.
I've never seen any post any gains for having a larger TB on a mostly stock engine like yours. It's not hard to change though....next time your at the track bring the stock TB w/ you and change them between runs and see which one gives you the best increase in E.T/MPH. That way you can tell what's best for your combo....cause they're all different, good luck.
Hmm, I ran 13.3 with street tires. If your using nitrous, you should break 12's. Guess it's true what they say, it's all in the launch. Then again, temp has alot to do with engine performance. If your chip is "Off the shelf" you need to get it dyno tuned.