[Elanshin]

You dont really need to see exact timings. Generally a quick scv count will give away whether or not there is a 2nd (or 3rd) barracks.

Assuming its not an all-in, the most likely candidate is a 1 rax FE -> 3 rax -> starport. A standard 1 gate expo -> 3 gate robo should get you into the mid game on par or slightly ahead if you delay his expo by containing him a bit.

However do watch out for fe-> 4 rax as the number of marines being output by that is surprisingly large and can overwhelm 3 gates if the protoss is greedy.

If there is no FE (and there is gas) then you should be very comfortable to take the fast nexus after core as any 1/1/1 is severely gimped and slowed by the lack of gas.

The only real other thing it can be is a 6-7 rax all in which just means get enough sentries to hold your ramp and then get collosus out.