To get perfect refine actually requires 2 different things: Standings and skills. On the skill side, you will want the Ore processing to lvl 4, Refining to 4 or 5, and Refining Effeciancy to 3 or 4. This should leave no wasted ore in a normal 50% reprocessing station.

However, for perfect refining, you need a station or POS with at least a 40% Reprocessing (with 4-5 in all relevant skills), and a standing of 6.67 of better (in the case of NPC/faction corp stations). This removes taxes so you receive the full amount of ore reprocessed. You can even achieve perfect refining in a 35% station, but you do need all skills to V plus a refining implant (can't rememberwhich one).