Size and Length of COPPER PIPE to use?

A Refrigeration Teacher at the University here will help me (with his students) to put together my Mini Ice Plant using a Brine Tank with Inside Measurements 2x8x3 ft.... Our question is, " How to setup the copper pipe or tubing inside the Brine Tank? Size EG:1/2 inch Inside or Outside Diameter?. Total length? Run a Single Pipe or Split One Pipe into Two or Three Pipes?"..

Specifications.
*3 Tons Compressor sealed type.
* 1 Condensing Unit.
* 1 Brine Tank 2x8x3 ft.
* 1/2 HP Brine Motor.
* ***** Tank R134A/R22.
* Copper Tube.
* Copper Return Bends.
* Copper Elbows.