Gyro

Gyro-P: Influence on the nick- roll- (rotation) speed. If larger, the MK moves slower.
Gyro-I: Influence of the angle attitude.
Gyro-D: If short control oscillations occur, this can be reduced with the Gyro-D value. If the value is too high, the MK begins to vibrate / hum. Setting: slightly below the value at which the MK starts to vibrate (20%).
Gier-P: Influence on the yaw (rotation) speed. If larger, the MK moves slower.
Gier-I: Influence of the yaw-angle attitude.
Dynamic Stability:

This value can adjust how much the thrust available to stabilize. If too large, the MK will raise during stabilizing action.

Smaller than 64 -> the thrust to regulate is limited under limit -> no rise in strong movements.
Larger than 64 -> the thrust to regulate can be larger than the gas value -> hard stabilisation of the axes -> could raise during strong movements
ACC/Gyro-Faktor: : The factor between the ACC-ange and the Gyro-ancles
ACC/Gyro-Comp.: : The angle fusion between ACC and Gyro-Angle.

Grad des Fusion zwischen ACC und Gyro (reciprocal). The smaller the value, the faster is the data fusion.The smaller the value, the more quickly adapted to the Gyrowinkel the ACC sensor. For slow hoovering higher values are better (> 100). For fast flying, you should take small values (10-50)

Hauptregler I: Sum of the angular error. Provides greater precision between stick and attitude. Can oscillate if the value is too large.
Driftcompensation (for FC 1.x):

Specifies how many 1/8 counts per 500 ms of the gyro-sensor drift can be tracked. If the value is too small -> the Gyrodrift (eg temperature changes) could pull the MK strongly in one direction. Null -> drift compensation off
/ \ NOTE: The FC 2.0 ME is the value is always 0!

GyroStability: reduces the influence of all three P,I,D
- below 8: lower influence of the PID
- larger than 8: higher influence of the PID

Tipp: if you want to change the behave of the MK, please first start changing the GyroStability and Stick-P and Stick-D

Setting up your gyro for smooth reactions such as for Aerial Video applications. (by MK-Flyer-SA)

Some settings are for when you input movements with your stick and want a certain reaction, other settings are for what happens either after you have let go the sticks or are doing nothing..

Noted below as follows: S = Stick input R = Return input

Gyro-D = R = under 10, makes copter sluggish (softer) to return from a user input. Above 15 very quick return from user input (harder) probably good for 3D but bad for aerial video. Lower values useful for larger copters and or aerial video. The copter has a natural dampening effect after a user input to return to neutral position. This setting has nothing to do with actual speed of user input i.e. exponential curves. If for instance it takes 2ms to reach a certain pitch, it might take 3ms to return to neutral with lower values. Whereas with higher values the stick input and return input might be the same, making the craft more agile.

Acc /Gyro - Comp = R = 32 standard. Higher values makes copter more resistant or less susceptible to wind changes and more planted. Lower values allow copter to be influenced by small wind gusts. Alternatively, lower values causes copter to over compensate and wobble, whereas higher values resist the urge to try and compensate for small wind changes therefore keeping copter more 'stable' which is good for aerial video. At a setting of 60, my copter was a bit 'loose' at 50 it was perfect, at 32 it was susceptible to wind influence.

Gyro Stability = S = below 4 copter sways and cannot get back to neutral easily. Use with caution. Above 8, copter jiggles and over compensates almost as if it is on springs and takes some time to stabilize after user input.

Gyro P and Gyro I = I have had both of these values on a poti and cranked them up and down with no visual difference to the flying characteristic of the craft and cannot explain these or what they do. For most cases leave them as standard settings. Please note the following when adjusting your gyros: Smaller motors with their smaller props (10") react differently (faster?) to the same board suddenly fitted with bigger motors and heavier props. Changing motors and props from a known configuration to heavier and stronger motors will not necessarily mean it flies the same. Each copter is different regarding final build, arm length, load and general construction, so each must be set up separately.

In summary:

Gyro-D lower numbers dampens stabilization, Higher numbers quicken stabilization

Acc /Gyro - Comp Lower values makes copter try and stabilize more quickly in gusts of wind

Gyro Stability Lower values makes copter very sluggish to find neutral. Higher values might cause wobbling

Disclaimer: These are my experiences only and not the outright rule. I only post my findings in order to try and clear up settings for new users or users struggling to find a happy setting..