Howdy
I have made both these items for one of my CMs. The first ones were labor intensive but now that I have it figured out it's not bad. The best thing about making them is that I can adjust tollerances to the individual gun. Assuming that I have it. I have a MKVII that has had a good amount of hot loads and the plug was getting loose ( I don't know why) I made one that fit oversize and it works great. I'm also working on an aluminum grip safety plug for weight saving.
Essex arms no longer offers parts for the "chopped" frame. about a month ago Brownells still had a few of the kits that includes all specific parts for the essex, they don't list it in the new catalogs so they must have been a poor seller. I have also made sear springs with good results.