Some paint questions for the guys who know paint

ok guys....sorry to sound stupid but I wanted to ask a couple of questions so I know FOR SURE what I want to know.....I have done some painting but I am not an expert or anything....My question is......I am going to be painting my 72 duster sometime soon(need to do some body work and what not first) but when I do,I plan on painting the entire exterior of the car,trunk interior,engine bay,dash and interior panels such as door.....possibly even the hole interior floor an all. My actual question is....how much paint do you think it would take to do what I have mentioned? I found the color I want (plum crazy pearl) I can get it for $90.00 a gallon for top coat and it mixs out 4to1 so I will actually have 5 quarts to work with....I wouldnt think it would take more then a gallon to do what I mentioned...what do you guys think?........question 2.......its a single stage top coat paint,im still debating on rather to run it only or if I should run clear...I like the luster of a clear coat but at the same time, I think single stage stays true to 1970s paint, what do you guys think...clear or no clear?. I am trying to stay cheap on paint but without the cheap look. going through summit racing I can get everything for my car for around $250.00,thats 1 gallon of paint,a quart of activator,a quart or reducer,a gallon of primer and a gallon of clear...or $200.00 minus the clear. hows that sound price wise to you guys?. anyways....in advance,thanks for you mopar guys and or gals help on my questions