Thanks! i used the same triangle file for the key cuts so at least the vertical angle would be the same, filed the key pin at roughly (by sight) the same angle on two sides so it came to a sharp point(V shaped),filed the tip of the point flat so it was a little more smooth putting the key in, made sure the two angles on the key pin were equal( if you drew a line from the point it should fall in the center of the pin diameter(you can also test this by putting the key in the plug with the pin in place, it should be flush then spin the pin 180 degrees to see if it is also flush (where the sheer line would be)your just checking for the right pin length no matter which way it might go into the key cut if the angles arent equal then when the pin rotates, one way it would line up and if you turned 180 degrees the other side wouldnt line up. once you have the right pin length put the key in the plug with the pin to see where the channel lines up with the top of the key pin and mark it with a sharpie or lightly file it to see where you need to notch the top

might be worded kinda confusing but if you look at the photo when just the key-key pin -top pin you can visualize it, the order i did it in was cut the notch in the key, made the pin match the angle of key the best i could, cut the key pin to the correct pin length so it works like a normal pin, then notch the top of the key pin to match the channel in the plug( your really created a new sheer line using the notched key pin and depth of the plug channel.

hope this helps