The default timers are fine as long as you are not using other scripts that are using up requests to mturk like hitscraper. If you are then you can push the number 2 button at the top to have it use the 2nd timer or number 3 for the third timer. 970ms is the fastest a script can go before PRE's are sent.
The script will slow down when it receives PRE's so if it slows down too much you might need to push the reset timer to get it back to normal. I have had good luck using the Stop Auto Slowdown in the options menu to grab hits.
What I meant by your own script is exactly what you have. Another script you use for captchas because I don't have one. There is no script that would fill in a captcha because that's against the terms so you have to fill it in yourself. Panda Crazy can only alert you to it.
The queue helper only works with organizing the queue it doesn't add buttons. You have to install the
Mturk Panda Crazy Helper. Once you have it installed and have Panda Crazy running in it's own window in the same browser then you will see two buttons next to a hit: Panda and Once.
You can always go to
http://pandacrazy.allbyjohn.com/ and find all the information you need. Sorry if some pictures are out of focus but I tried my best.