I'm very glad you decided to talk about your 1883-O interest. Fascinating things can be found in this VAM
thing! I'm a recent convert of about one year and only find time here and there to hunt for them. I am going to go back and read the posts you linked for reference.
I wouldn't say I am focusing on any certain issue, but I find myself drawn to the 1900O and 1880O series more often than not. And, who doesn't like the endless "crackiness" of the 1921Ds!
I recently joined SSDC to gain access to their library. I haven't been on the VAMWorld forum very much, but will also look for the discussion you mentioned.
You are a valued resource here on CCF! Thank you for the many times you've answered my questions.
"Nummi rari mira sunt, si sumptus ferre potes." - Christophorus filius Scotiae