For portable set, the best choice would be HDPE, ‘Quick coupling sprinkler pipes of 4 Kg pressure rating , which being portable in use , can be assembled and dismantled easily and Raingun can be placed every half acre progressively using portable trolley stand with wheels for mounting Raingun on its supply pipe.
For larger area, Rain Gun can be positioned at say 120ft x120 ft in the field using underground PVC or HDPE pipelines of 75 to 100mm dia as main supply line with above spacing outlets, and connecting to it the 63mm or 75mm dia portable laterals of HDPE sprinkler pipes on both sides , having the Rain gun with trolley stand attached to its end. Rain gun unit gets moved such that it covers the entire area progressively.