Okay, i get the basic idea and i would like to start practicing them.

My first question, were is no mans land, what hieght is to low but to high, if you know what i mean.
The second, should the collective be braught to full negative, like -10 or 11 or will that actually act as brake to the blade?

For your first question, I don't know the plot of the "dead man's curve" for models. The full size helis, each different type has that info in the flight manual. It will differ with different models also. Sometimes I feel tempted to experiment, but I haven't given in yet.

Regarding the second question, typically around -2 or -3 degrees is what you would use. It's about the same for full size helis.

But, as with full size helis, if you're hovering near the ground you don't go negative. You might make your first auto from a 2 foot hover, where you don't have to do anything other than increase collective to land soft. It wouldn't be bad if you didn't do anything. From that height you can take your time. From a 4 foot hover you won't have as much time to mess around.

If you're motoring through the sky when you drop power you want to go negative (-3 deg) right away and hold that and maintain forward speed. When you're around 6 feet pull the nose up enough to trade off speed for a slow descent. Be sure to get it level before the tail hits the ground. As you level the skids come up to hover pitch. From there it's like a hovering auto. If you still have forward speed be sure to keep control of the heading. You don't want to hit the ground going sideways and you don't want to burn up all your rpm trying to get fully stopped. If the ground is smooth it doesn't hurt anything to land with a bit of forward speed if the heli is heading in the direction it's traveling.

Tighten up the blades a bit in the grips.

Bump your throttle hold up to keep some blade speed at the bottom and lower it back to an idle as you get the hang of it.

Here's a good tuturial.
http://www.ronlund.com/autos.htm

My first auto was forced today becuase my torque tub dog bone came loose and the heli started spinning uncotrolabley. Anway, i todally over corect and flared about 50ft to high LOL. Then i went down another 50 ft and flared again. I would call it a milled crash but no blades hit the ground. The only "damage" was me having to clean the darn thing after the skids dug up some dirt. I cleaned her up, fixed the dog bone, and headed out to the local park. I got her up into the air and decided to start some auto practice. My first complaint was that the gyro was set way off. I increased the gain from 50-80. Was running 70 on most flight modes. I am thinking of even going up to 90 because when i switch to throttle hold the tail still moves. I worked my way up from 5ft to 10ft and by the end of the day 30ft. 30ft was in my opinion no mans land. I kept bouncing it when i hit the ground and couldn't for the life of me could not get the flair right. The ones i did get perfect were really cool. Anyway, the last auto broke the landing skids, they just couldn't handle all the bouncing around . Anyway, i ordered more landing struts and will go at it again nect weekend.

I have to give my compliments out to the hawk/os .37 combo. It is so stable, durable, and has so much climb out from hover. It is like a rocket!!!

It is hard to define a "Dead Man's Curve" on model helis. I guess it depends on the condition of flight. If you make an intentional auto with enough headspeed, any altitude should be sufficient. If you are forced into an un-intentional auto on the "normal" (low) power setting (barely enough headspeed) then you could be in a world of trouble if you don't have the altitude to maintain the headspeed all the way to the ground.

Rafael