I'd like to enter the world of electronic hobbies by making a railgun, and so far I know that I understand the basics of the device and that I need high amounts of direct current.

However, I am puzzled, as to where to begin calculating. I'd like to set myself X amount of joules/kjoules of electric energy and work from that, but I know stuff like rail length and how the rails push eachother apart would affect performance, so I'd like to know;


How Farads relate to Joules (I know the J/V^2 formula but that wasn't clear enough)?
Should I opt for a single powerful capacitor or a bunch of smaller ones, especially since I want to unload the charge as fast as possible?
What kind of conductive metal should I use that would be both conductive enough for acceleration and durable enough to resist the recoil and other forces involved?
How should I cool it or deal with the heat? 
Would there be much heat to begin with in a portable railgun?
Would ABS coating be a proper body for the gun, protecting the user from the lethal amperages that will be involved?
How exactly does rail length help the case, as I would use a bipod for a long rifle if that will increase my efficiency?
Would it be a better idea to have conductive bullets, insulated bullets with discarding and conductive sabots, or a stable aperture that will simply stop at the end of the barrel by whatever means I can come up with while letting the unbound insulated bullet out? 
Should I keep my circuit simple as to just use switches, a battery, capacitor, and some LEDs, or are there more efficient circuit components?
I'd like to have a control mechanism that lights the Red LED when it is charging, green when it is charged, how can I do that? In my simple sketchup of the circuit I have V-switches (don't know the technical name) aligned in a way that the lights should light correctly during the course of my planned three stage trigger, but better ideas are obviously welcome.
Will a capacitor lose its current when neither of the ends are connected to a complete circuit but both of them have wires attached to them? I am guessing not but better safe than sorry.
Is there a way to make sure the capacitor has depleted its entire charge? 
What would be a good idea to improve safety and efficiency?


Thanks in advance!


Question: let you know a couple of facts OR bring couple of facts to your notice
Answer: Whenever you are writing to someone it's really important to use words that sound polite. So it would be better sounding to the reader if you use "I would like to bring a couple of facts to your kind notice/attention".