1 The LSD story....he was using a solvent cleaner. Solvents can carry "stuff" through the skin easily enough. When working with solvents, wear appropriate protection.
2 Eating pot vs smoking.....when you eat it, stuff goes stomach, small intestine, then into the blood vessels going to the liver and onwards to the heart. When you smoke, stuff goes to the lungs, then into blood vessels that then go the the heart then up the head. The key difference regarding "strength" is the chemistry that happens in the liver: THC gets turned into a more powerful psychoactive before going to the brain. Key difference regarding "duration" is speed up of transfer into the blood to brain (slow trickle versus all at once).
3 Sleeping well takes practice. FWIW, sticking to a bed time ritual, limiting caffeine, getting some movement based exercise during daylight hours (outside better than inside), writing down things that need to get done (so I don't have to actively remember them or fret I am going to forget), and a few other small things, have helped me sleep.
4 Melatonin is a prescription-nly drug in Switzerland. Our Swiss friends buy up about 1000 tabs each when they visit. I smile when they ask me, "Is this a good brand? Do you know it?" They also can't believe how cheap it is here. If you go to Switzerland, bring some melatonin for resale to help fuel your endless winter.
5 Cold water surfing has profound influence on my sleep. With one hour of cold water surfing, sleep fine at night. With two, I go to bed a little early or doze a little while watching whatever on the telly, sleep like a long dead fallen Ponderosa when I do get into bed. Three or more hours cold water surfing, it is like, "Can we hold off on the nuptial activities...how about 12 hours from now when I wake up?"