From a web search, 30awg has a resistance of 10.32 ohms per hundred foot or 0.31 ohms for 3 feet. At 20mA, that would drop 0.006V. At 60mA (the cathode with all three on), it would be 0.019V. Total drop would be 0.025V.
In other words, it will work fine. Even at 30 feet, the drop would be a quarter volt and would still be fine.
/mike