I have to admit to a curiosity about catheters myself, although I haven't tried them. Specifically, I was wondering if the flow would be a discrete on and off, a continuous dribble, or both under different circumstances.
It's both

I thought it would just be a constant dribble but it depends.
First, there is a constant stream as soon as the catheter enters the bladder as the bladder empties out. After that it stops for a bit. As you move around though the remaining pee in your bladder also moves around and finds it's way out, so there are small spurts occasionally as you move. When you reflexively clamp down due to the MUST PEE NOW! feeling there will occasionally be spurts of pee that come out as well.
The rest of the time there are pauses and then some dribbles while your kidneys are processing and excreting pee. Bladder drains, pause for a while, enough pee builds up to reach the catheter level so it dribbles out.
Imagine a leaky faucet that drips into a sippy cup every few seconds. It won't overflow and spill out of the cup continuously. The water level has to exceed the top of the cup by a certain amount before it overflows and lowers the water level to just under the top of the cup. Repeat. Your kidneys would be the faucet, the bladder would be the sippy cup, and the catheter would be the top of the sippy cup where the overflow spills out. The length of the pauses and volume of pee would vary depending on how your body is processing and excreting fluids.
Note that in all instances you can not feel the pee coming out like you normally do. The only thing you can feel is the continuous "MUST PEE
NOW"! feeling. I noticed from direct observation while not diapered or while the diaper was open.
About the wiki, sounds like a good idea to me. I suck at creating something from scratch though so I won't be the one creating it. I am good at editing so if someone else builds it I'll be happy to edit.
I agree with you about not going into how to purchase and sizing. It would also be good to start out with reasons why it is a bad idea (UTI, internal trauma, whatever else I'm forgetting right now). However I do think that there should either be another wiki or a pointer to where to find information on how to be as safe as possible. I know that seems to go against not providing specific how-to bits, but I expect that regardless of how bad it sounds or how strongly it is recommended not to do it there will likely be someone who decides that they want to do it anyway. For those (hopefully few) people I would like to make sure that they have as much information as possible to be as safe as possible.