Thank you, I will be getting some of these.
I would definitely consider putting these in the back of the cylinder. Those springs look tough, I bet they would wear down a key faster.
On another note, from the shape of the top pin it looks like it might be designed to catch like a typical security pin if there is lots of tension on the plug. Also I wonder if these would also affect somebody's ability to impression a key, maybe those top pins would give the false impression?