evaporator question

[JohnFish]

will start building my chiller later this week so I am planning to start with the evaporator.I am thinking for a simple tube in a res approach but i want it to be as small as possible. So i have a couple of questions.

1) thinking of using a large tube, something like 80-90mm diameter that will contain the refrigerant tubing inside (coiled). Will this work?
2) How long does the evaporator need to be approximately (was thinking of 10-12')?
3) should I go with 1/4 or 1/2 tubing for the evaporator?

Thanks in advance.

Edit: Another question, does the res need to be large enough to be able to hold some fair amount of water because I dont think that using the above evaporator it would be able to hold more than 0.5-1 gallon of water.