This segment actually relies on a bit of player skill and good timing.
You have to time it so that he's face away from you as you sneak over to the right side, and be behind the rocks by the time he turns around and starts heading left.
Alternatively, if your climbing skill is really high, you can actually climb the wall on the left side instead of having to go to the right side, thus enabling you to practically skip most of the difficulty here.
Thank you! I have tried this about fifty times by now and nothing seems to work; I'll try climbing on the left side and hopefully that will get me through!
There are also two things you can do to help. Cycles aren't going to make too much a difference, but game speed (+/- keys) will. Turning the speed ALL the way up will actually give you "more" time; you'll need better button control, but you can get SIGNIFICANTLY farther before the game checks to see if Toro can see you.
The second thing to do, also, is to wait in the bushes and move "Up" before moving out. For some reason, this seems to cancel the bush rustling animation. The other alternative is to make the bush rustle on the high speed above. I found these little trick of the engine out while working on the tool-assisted speedrun of the game : https://www.youtube.com/watch?v=K4CU5VHU1Gg
Zachski's advice will probably work. Really, you don't actually need to worry about the quality of your Stealth skill with Toro. He's even easier to handle than the Kobold (who needs exactly 35 or more).