Looking great man! But I think your first barrel tip was closer to being correct (not so much of a taper going on). Here's a compilation from the guru, Brak's Buddy:
I'll dig for my drawings too.
EDIT...here was my initial take on what the tip would look like:
Like I mentioned in my email to you though, it's going to be tough to get the "definitive" barrel tip until we can find some better, more clear reference pics.
Again, you're doing a spectacular job!