You should ask Breeco, who is a SOLO world pro
Well, I doubt how much Breeco can do in solo, He is an excellent diplomat but I doubt him in wars.
He got his e5 win because of me only, so trust me
Coming to charles,
In start I boost metal,worker,oil till 100-120 tick, then boost workers as ads said,
for structure, I give gate first importance and always make vehicles structure.
As for as radar keep it to level 3, for farm upgrade it to level4.
Rest of resource structure level 3 is must