That is a Lyman globe sight. It has interchangeable inserts. I like the one with a hole in the middle.That sir, is exactly the information I am after. Even the set up looks like what I'm out to do with my 54 GPR. Still have to make a wedge for the TC peep I have. What kind of front globe sight is on your .54? I haven't looked into a globe front sight for mine as of yet, but its on my To-Do list.
35 grains of 3F is fairly economical.