When it gets that deep into the woods, I just throw my hands up and send it to John. I just got an 1887 O, MS62 + coin in hand today and it looks like a VAM 2, doubled 1, tripled 7 but I'm not sure. I'll try and scope it this weekend and post it here. It's a top 100 VAM if so, but PCGS did not attribute it. They won't unless asked to. I bought it this week, looks like a nice sleeper coin, conditional rarity with a top VAM on top of it for a reasonable price. Sniped on eBay? But of course.
I don’t know about VAM varieties. They have never attracted me although I do have an early edition of the book. I have a five opening Capital Plastics holder for 1878 dollars. I filled that plus a sixth variety, which should have been included, the reverse of 1879. That was enough for me. My attitude is buy five, or six, really nice pieces that you really like; and end it with that.
My 1878 silver dollar collection has not grown in three decades. I really enjoy looking at them and studying the history, but it ends there so far as buying more of them.