I'll answer the part about paper. I use paper a lot, and I also use computers a lot. Yes, I use a whole sheet of letter-sized (8.5 by 11 inch, usually) paper for each action, in some of my systems. (In other systems I have multiple actions on a page, e.g. in a notebook in my pocket, or items listed on computer.) To avoid being very wasteful, when I finish with the action, if there are only a few lines of text written on the page I erase it. I use soft pencil leads (2B), so it's easy to erase. I sometimes re-use a sheet multiple times in this way. If one side of the sheet of paper is full, I cross it off and use the other side for other actions. I also collect used paper printed on only one side and use the other side to write actions etc. Sometimes I cut up a large (used) envelope into one or two sheets of paper. I also cut up smaller, business-sized (used) envelopes into several smallish pieces of paper for writing notes to family members, reminders to myself taped to the fridge, etc.
I really like having the actions one per page, so that I can sort through them and easily move them into different piles. The page also provides room where additional information can be written.