I haven't been active for a long time... But this is an important thing to know.
As it happens, i am somewhat of an expert in pooping - Having DOZENS of years of experience.
So let me tell you:
1. Over. But even better: Loose roll on the windowsill.
Paper: 3 Layers. 4 is for rich people with no sense of right and wrong, 1 or 2 layers should be forbidden by LAW.
Additional information for your pooing and wiping benefits:
1. Most people poop better when they are naked... why? How? No idea, but i do take my shirt off and it feels better... strange.
2. Squatting is also WAY better. I do have a footstool and a turned over flower pot by my toilet for my feet. Feels good, man. (Also faster, cleaner, apparently better for your ass)
(These guys want to sell you stuff you don't need, but still):
3. Clean your damn ASS, people and CONTROL yourself when shitting in a public toilet. There are some disgusting animals out there using the public toilets... THE THINGS THAT I HAVE SEEN.... Oh great Cthulhu, help me...