I'm only about 10% with what I've received. I think I have some good addresses for what I haven't gotten back so it's just a waiting game now. I still have over 1/2 of the addresses to get though. Slow process when I only have a couple hours a week to work on it. Still a fun challenge though.
Working on sets is very time consuming. It was so bad, that I had to take a break from it all together. I'm currently building the 90F and the 94T sets. You should sign up on SCN. There's tons of addresses, private signings, and success rates. It has helped me with toughies in my collection.
I have 103 from the 1991 topps set... if you are looking to buy, LMK and I can post a list. I have a bunch from the other sets you listed too... I typically sell common easy signers for $.75-$1, and up from there depending on star quality and toughness to obtain. LMK
I probably have a couple in my collection from putting together the 1987 Topps set signed. I am at around 490 of 924 for the base and traded sets.. shoot me a list of your 87 signed traders and I will see what 91's I have