NowhereDan, the attack command isn’t alt click, it’s ctl+alt click, which is the dumbest attack move command since Age III used the ‘z’ key. Ugh.
Matt, the question about base size is a tough one. Basically, like most RTSs, you never stop building your base. Once you’ve got T3 engineers, you want to be building T3 power stations and T3 mass fabricators, presumably to accelerate production of an experimental unit.
As wonderpug noted, shift placing ferry routes will let you set up a ferry path and the transports do indeed return over the same route.
Also, I think some of you missed NowhereDan’s point, and it’s a huge one: you can delete things from patrol routes, waypoints, build queues, or anything else displayed on the map by ctl+shift+rightclicking. Don’t want that one mass fabricator sandwiched into your build among a bunch of other mass fabricators? Just ctl+shift+rtclick it’s ghosted image.
And, no, a lot of this stuff isn’t anywhere in the manual or tutorial videos. Way to go with the documentation, Gas Powered.