Sharing Etiquette

Two questions

  1. What is the recommeded etiquette for seeding and leeching. Example if I leech until 100% then how long or how many days should I then seed the file that I just downloaded. I do not have unlimited space on the hard drive so I have to burn the files on to a disc and then delete the file in order to continue.

  2. I have files I can share if those are in need of sharing but I have to know who needs a certian file in order to share. Is it possible to have a forum for those who may need portions of a file in order to assisit them in completing there tasks.