The reason Desoxyn was so darn good years ago was that the 15mg extended release tablets were common. The tab was some kind of plastic thing and the meth diffused out of it slowly as it went through your GI tract. You just pooped the intact, spent, tablet out.
It was the perfect formulation for IV use. You just soaked the tab in water in a little bottle and the meth diffused into the water. Often, you would set the bottle on a light bulb to slowly boil and facilitate this. You threw the tab away totally intact when you were done. No talc, fillers, buffers, and all the things which make shooting pills dangerous. You had a lightly yellow but otherwise clear water.
I've actually heated a nearly spent tab in a spoon (you would soak a couple/few times) and pressed on it with another spoon while it was hot. The tab mashed flat but popped back up into it's original shape when I let up on it.
3 or 4 was a nice shot. Remember, you didn't get it all the first soak. You did get most.
I generally did 5

, but a quick and dirty soak so who knows how much it was. Plus, I'm tall, so even as a speed freak I weighed 190.
Once I was cranking, getting the last out was fun. All about the ritual, you know.