I have not touched a Blade 400 is a year or maybe two, but they used to supply a re-labeled Telebee gyro. This is what I call a "label sideways" gyro. Because on a helicopter tail, it points sideways.
Like this one:
IF that's your gyro, then you would want the label facing up or down, and the wires coming out the aft/forward end.
Then revese switch set as needed.
As far as the horns go, my general rule I apply with or without a gyro is to try to use the point on the horn of the control surface as well as the servo as far out as possible and get the travel from the surface I want while having the travel adjust on the TX set to 100%. That minizes the slop and flex effect of the rods on the control surface movement and gives you maximum servo resolution as well as torque. If the instructions for example said get 1" difflection and you had to set your travel adjust in the TX to 50%, you have now lost 1/2 of your servo resolution and torque. You get servo speed but that's negated by the loss of torque and all the slop you have to compensate for (fish tailing when setting trims).
I"ve already touched on slop at mycoolrc.
I have cheap gyro and dirt cheap servos in my Hawsky. They work, it's more stable with the gyro in the wind, but as mentioned in the optimizing page, it's not as stable w/ my 48" Extra that has ball links, digital servos, stiff surfaces etc.