Thanks for taking the time to read this. I want to confirm my thinking. The throttle limits on the KK2.0. If I set the limit to say, 70%, the KK2 or ESCs will limit the motors output to 70% of its maxim power, is that right?
Throttle limit on the radio? Don't do it there. Look instead at stick scaling on the board. Stick scaling will take the throttle input and give you a percentage output -- 100% throttle from the radio with 70% scaling => 70% output to the motors.
The reason this is better is the throttle limit reduces range the radio can command, whereas doing it in stick scaling the radio sends the full range (and you keep full resolution in control) and the board interprets your wishes through it's setup -- the clearer your wishes are, the better the board can do it's job.
To answer your question directly . . . no. stick scaling won't hard limit the ESCs either -- The problem is in the mixing. The instantaneous speed for any one motor depends on a lot of factors, not just the master throttle output. It also depends on the any roll/pitch/yaw command which will increase or decrease the motors speed above the master throttle to accomplish the maneuver. If that's not enough, the correction loops (gyro's P&I loops and accelerometer's P loop) can add even more throttle on top of this. The correction loops can be limited with their P & I "Limits" setting, but this is kinda hard to convert to a "limit of 50 means X points of throttle".
If you're worried about overstressing the motors and ESCs (I'm assuming it's why you're using a "magic number" of x%), it'll be hard to predict -- better to test it out. Fly briefly with a 70% scaling and see if the motors or ESC get hot. Not warm. Hot. It's the heat that kills these guys, so a brief small burst above the limit won't break it.
Also, one thing that might help is that you are not anywhere near full power when you are hovering. It sounds like you are worried that you are too close to the limits of your motors or ESC's...? If so, and you don't have a wattmeter to test actual current draw, hover for a minute or two, land and immediately check the heat of the motor cans and the ESC's. If your response to grabbing a motor can or ESC is to yank away newly blistered fingertips while yelling obscenities, then you will probably want to do some shopping for other motor's or ESC's, depending on what caused the burning sensation. If, on the other hand, you can hold your fingers to them for a few seconds without blistering, you should be fine with running what you have now. Once you learn more and start doing more serious maneuvering, you'll want to perform the heat check again to be sure you are still not over-stressing anything.
When I was learning to fly I set the stick scaling to 30% and on the radio dual rates of about 50% with a 20% expo. This made it quite docile and not scary. I spent days flying away from me and then back again (going backwards), then I would practice moving left and right. Then I stood in a large field and flew away, yawed to face me and then slowly flew towards me. Then turn and back again. All very boring stuff but the core needed to learn to fly a quad.
The other thing I found helped was lights, white and red (but only facing in one direction rather than wrapped around the arms, if it was wrapped it all blurred and didn't help). I would then fly early evening, the lights helped instil confidence with orientation. This eventually rubbed off into day time flying. I still have "Oh bugger" moments but they are few and far between
I now have the stick scaling up at 100 ish and this is enough for flips etc... The only thing left dialled in is the expo.