Starcraft – How to hotkey an allied unit

If you go to options, hotkeys you can assign it to whatever you want. It is called camera-save. By default though some menus take up f9 - f12, so ctrl+f8 is the only one that works for camera saving with the default profile. You either need to pick different keys or take the menus off of those hotkeys to get the other ones to work.

While you're attacking, pay attention to his economy & tech status. Do you see chrono boosts on an upgrade? Is his unit composition hinting that he's going to transition to something soon?

Did you kill any workers? How much army did he have left when your attack ended?

If you can put these together, mixed with a lot of practice and game sense, you can evaluate whether you are ahead or behind. In fact you will have the tools to know much better than he does, because you were at his base scouting the whole time.

Honestly it's not that important to know this though, because how would it affect you? Either you know you are so far behind that you must make a last-ditch all-in, or you know you are so far ahead that you can expand yet again and still hold anything he can throw at you or counter anything he has.

Anything in between and you should be careful to assume either way, as your game sense gets better and better with practice. Keep scouting.