How far have you gotten on endless mode?

I have made it to map 31, but it is impossible to beat it. I always use 3 Valiants. The command ship is configured with every slot but one filled with fully buffed shield boosters. The last slot has my most powerful shield drainer. The hangars house buffed repair drones. The other two ships have every green slot filled with buffed shield boosters, and the red slots filled with my most powerful beam weapons. The hangars house buffed bombers. But every time I enter the last sector, I lose one ship nearly immediately and the other two usually before the engines recharge. Once I was able to save the command ship, then I had enough scrap and resources to buy and equip two more Valiants. I went back, hoping that the nearest one had been weakened enough to destroy, but I got killed anyway. The distress signal gambit won't work because the last sector has four bases in it. They don't move. These four bases are armed with super powerful, super long distance beam weapons. I have a trick for saving my game at any time and restoring to that state.