1. No need
to rack it, but I would after 3-4 weeks to get it off the lees. If it is sufficiently clear for you you could go right to bottles
2. What do you mean my "better taste"?
3. Well, most apple juices fall in the 1.045 - 1.050 range. If you know how much the sugars weighed, you could get a close estimate.
4. It depends on how carbonated you want it. For only one gallon, you'll probably want no more than an ounce of sugar. You can figure this out using an online carbonation calculator (like this one here - http://www.tastybrew.com/calculators/priming.html
). When you bottle is really up to you. You need to make sure that it is done fermenting, but some people bottle ASAP after that and others let their cider bulk age for months. Bulk aging will help with the clarity as all of the particulate matter drops out of suspension.
5. Pectic enzyme is not necessary, but you could add it now to help speed up the clarification process.