Hi J.! I also have a 16 month old who is still nursing and is incredibly attached. I have not yet weaned her, but I can offer some insight that may be helpful for your little ones sleep & yours! When my daughter was about 14 months, after reading the No Cry Sleep Solution and other very gentle guides to get her to sleep we found that none of them yielded significant results for us, after much patience and persistence. It was at that point we decided to try the Ferber Cry it Out method. I never in a million years wanted to do this, but I was at my wits end!
We knew we wanted to do cry it out, because after trying every other way, we weren't left with any other options. We did it during a week when my husband was off (he's a teacher). If you can't do that (and who wants to spend vacation exhausted?!), you can start on a Friday.
I never did cry it out, because for the first 8 months of her life she was in our room, as we were in a 1 bedroom apartment. Then, when we moved to a 3 bedroom house, she was just so conditioned to being tended to immediately, that I just couldn't imagine having her cry. It really was out of complete desperation, strong encouragement from my very patient husband and me being so exhausted (I was a zombie, not socializing, had put on weight-it was just bad!)!
As for her sleeping, when she first went to bed we did her usual ritual which consists of the following:
6:00PM ish- dinner
6:30PM ish- bathtime
7:00PM- lotion up the baby, put on Pajamas, run around a little in the living room, read a few stories with daddy
7:30PM or 7:45PM- mommy read stories in her bedroom to baby for as little as 5 minutes as long as 15 minutes- nurse for 5-15 minutes, rock baby for a minute or two
8:00PM or 8:15PM-put her in her crib awake. We also use a white noise machine and have a small nightlight in her room, as it's very dark. Nothing bright, just enough light so she can see her surroundings
We would watch the clock and go in every 5, then 10, then 15 minutes. I could not personally go past 15 minutes (some don't go past 10, others continue to increase the minutes by 5 all the way up to an hour-you decide). She was crying so incredibly hard, saying "mama! UP! UUUUPP!" and clinching to the side of her crib. It was one of the most difficult times in my parenting career. She seemed to be less worked up when my husband would go in there. I think it's just because it's mom and I still nurse her. Anyway, when we would go in there, use "key words," which oddly is something I learned while reading the no cry sleep solution. Use short phrases and words, such as "Night Night Baby," "Go to bed," "Mommy loves you," "Time to sleep sweetie pie," etc. We would not pick her up, but would pat her back, kiss her forehead if she was standing. Basically, we would quickly reassure her, shower her with affection and get out fast. I would not linger tried to keep my visits to 20-30 seconds at tops, less if you can! We would use the same method for nighttime wakings, which were shorter than the initial time she laid down for the evening.
I haven't mastered naps yet, and often nap with her still. Lots of things that I have read say, be consistent. We are consistent at night, however she was crying through her entire naptime, so for me I will nurse her until she falls asleep and then carefully set her in her crib. We are also trying to transition from 2 short naps to 1 long nap, so I just wanted to make sure she was getting rest still during the day. I plan on having her cry it out during the day if we can't get her to be a better sleeper at naptime soon. With that being said, we are still very successful at night and are reaping the benefits during the day- she's often much easier to put to bed at naptime and she is less apt to be whiney/fussy when I leave the room or she's not getting what she wants.
It worked very well for us, but is not for everyone. I told my husband we would give it a week. Within 3-4 days of hard work, we saw results. I just felt like my poor little girl did not know how to go to sleep and was so, so tired. I hated hearing her cry, but knew that a well rested baby = a well rested mommy = a MUCH happier family all around. Feel free to email me with any other questions you have! Good luck to you!