Seriously guys, can we not just all get along? If Astaeri doesn't want to carry on with the tournament then it's no biggy.
That was more a (bad) example of how I'd build the wrong units not a specific example.
I'm pretty good at using my early lings to scout around and always leave one at their natural. But once they have a wall with a cannon or 2 and some stalkers at the top of the ramp you don't exactly see much.
I'll try sacrificing an overlord at 7 mins for a few games to see if I can get a feel for the various builds.
Do you tend to always keep plenty spare overlords for this? I probably need to overbuild them a bit and sac them more often just to learn.
I never sacrifice more than one overlord really. Maybe if there is an unusual quiet period in a game where they might be doing something a bit strange I'll throw in another one, but that's extremely rare.
With scouting, you have to really consider what options a protoss has. Like all the races, they can't do everything at once, so certainly at the 7 minute mark they are either doing one thing, or many things badly.
Say you're at around the 5-6 minute mark and they have a complete wall. Your ling at the bottom of the ramp sees that there is no expansion. Really, there are only a few good options a protoss can take:
a) 4gate
b) DT rush
c) Air rush
d) Expand
So move your ling up the ramp slightly, what do you see? If you see a large number of sentries, straight away you can throw out air and DTs. A protoss can't afford the gas off one base to have a large number of sentries and other gas heavy units. More importantly, be suspicious of what he's doing with the minerals. It's highly likely that the protoss will be using the minerals to expand soon.
What if there are no sentries? Well where is the gas going? Suspect air or DTs and react accordingly.
It could be that if you spot say, no sentries and in fact they are just rubbish. They could not be going air/DTs and instead have 500 gas in the bank. Fantastic, this guarantees you the win

. So what if you spent a drone on a wasted spore crawler or 2 and a few extra queens? This is negated by the fact that you can produce 20+ extra drones whilst they're screwing up their macro and win later on in the game

.