Alright! The piston is out!

Unfortunately, none of the common wisdom from above worked. Frustration set in and, eventually, I decided to try and pry the group from the boiler. Gently at first, then I went Hulk-syle and bent it with fury I think the pin was supposed to come out from the front easily but mine was seriously stuck. Anyways, once I bent the boiler away, I was able to push the pin from the back out with a tiny screwdriver. After that, the rest was easy. Took apart the entire piston in a minute and gave it and the group cylinder a JoeGlo bath. I hope putting it back together goes more smoothly.

Thanks for all the help folks. Now, some pictures (because there are some very slight differences with Francesco's Little)