A few things..
1) Hydrochloric/muriatic acid also works wonders to clean a pipe. Just put a few drops in and mop up with a Q-tip or burn it off with a torch. It's never failed to get a pipe 100% clean and brand new looking.
2) Use a Pyrex pipe. Glass pipes are very sensitive to heat. Constant or high heat can deform them and cause the glass (especially around the hole where you load the bowl) to become very thin and brittle. Pyrex can withstand extremely high heat -- I've never seen one get deformed one bit. The only problem is most speed bongs need custom pipes.. which means glass.
3) If you can get or make a speed bong.. use it. The hits will be huge, will not be harsh, and so forth. Fill it with Fire water, water and some Altoids, or something else to give it flavor

Then when you're done, drink the damn water, its full of speed.
4) Normally putting your finger over the mouth end of the pipe can also stop the speed from escaping if you're out of breath. This stops the airflow so the speed just swirls around in the bowl. I've never burnt myself putting my finger over the carb hole though.
5) You -CAN- load too big of a bowl. There is no need to load huge bowls.. it will just become more difficult to melt it all down and you are more likely to overheat it and burn it.
6) The reason speed lasts longer if you melt it down and spread it around the bowl is this (I think, correct me if I am wrong): if you have a thick puddle of speed in one place on the pipe and heat it from the bottom, the bottom of the puddle is getting MUCH hotter than the top, but cannot smoke as easily because there is a big layer of liquid on top of it. Thus the bottom layer begins to boil and burn, wasting the drug and making a mess of your pipe. Spreading it thin ensures this does not happen.
Peace.