Woah man that's impressive. I've played through the HD campaigns (their DE versions) and currently am doing the DE campaigns. Everything on standard. I want to do it all on hard but I don't like losing so hard lol
I remember the 5 ships mission. I beat it by blocking the first ship in the starting area with my own ships, so it would never reach the destination. I then slowly constructed a base and defeated all enemies before eventually letting that first ship cross. I never thought about saving between each shipment lol. Would have helped me beat it the "right" way.
Maybe I should shift to hard difficulty. But based on what you say it seems like a lot of pain will be waiting for me that way