I've said repeatedly that anyone can have all the resources they want when they attack me. I get back what they take in two raids anyway. It's working for me. Again, when I start to see deathsaurus and deadend solo'ing my base, I'll adjust. But for now it's holding out against any teams under 8k squad power. Harvesters have half the health as storage, and would not do the job. I put storage up there so I have a reason to use fuel once i get four of my build bots working. I'm also trying to stagger my upgrades now that they're hitting 7 day durations so I'm not maxed on resources for five days straight.