A 50cm line on the sides will work fine for just about all configurations. A 150cm line on the front and back with a peg loop tied at the end and an additional loop tied at around 30cm from the tarp should enable you to utilise every option without the need to change or swap lines.
Loosely peg out the rear line and one side line. Insert your pole into the ring at the front of the tarp, stand the pole upright and peg that line out too. Now peg the remaining side out and then adjust all pegs as required to pull the tarp taught – remember, the angle of the lines in relation to the tarp will alter how the tarp sits. 80cm – 120cm pole length is ideal depending on the set-up desired (pole not included).