Help with methane and distilling

[hockeycns]

I had a question about distilling in general. I have researched the "2 dolar crock pot still" (Diagram posted)

Next I looked at recipes. I have heard of some people distilling brand name alcohols to make them more potent. The method that intrigued me the most is using superyeast and fermenting a 20% alcohol base just as you would do with beer and then distilling that.

My few questions that I have about distilling are about methane, time, yield, and dangers.

Ive heard people online say that the first 5%, 10%, or 20% of the liquid that comes out of a still has to be removed because of methane. Is this true is one were to put a brand name alcohol or a superyeast batch through a still? also why is methane produced and what are the dangers of it?

How long does it take for liquid to go through a still? does temperature matter/what is the ideal temperature?

I assume that if you distil a 20% alcohol through, when you are done it should be roughly 1/5 the original amount if you are making close to 100%. Is this right? also with each pass through the still how much more potent does the liquid get?

Lastly, what other dangers come with making moonshine/home distilling?

Thank you guys and sorry about all of the questions, i am very interested in this subject and want to know more.

Thanks again!