With 5% "tax", you will only make a profit of max 120, and in some cases you will loose money
Yeah that's why i emphasized quantity, if you have a full trade pile of players that always sell, that 120 coin profit x 30 = 3600, do it for 3 or 4 hours or even just before going to bed and when you wake up at least 25 of the 30 players will more than likely have sold in a 6 hour auction. Works a charm for me.