I don't know if this helps at all DH and I apologise profusely if I'm teaching how to suck eggs. If nothing else, I'd be interested in comparisons between my technique and others? I just kinda make stuff up as I go along with this whole baby care thing!
I have a chair in the nursery and after the nap/bedtime routine I sit silently with M in my arms to settle her. If she's wound up and/or fighting sleep, I sit her up a bit to start with and hum. Once she starts to settle, I recline her more in my arms until she's mostly asleep and laying horizontal. Then I attempt to carefully stand and put her in the cot.
If she stirs and squeaks as I set her down on the mattress, I freeze and stay leant over her for a few moments with my arms still underneath her. If she resettles, I carry on slowly extracting my arms. If she wakes and gets upset, I immediately lift her out again and go back to sitting silently until she's settled and I can try again.
The whole thing takes about 10-20 minutes and two set down attempts on an average day. But can work on the first time in 5 minutes on a good day and take an hour or so on bad ones.
At night now she settles pretty fast and I often put her down awake after her bottle to sleep, but I still have to follow the above routine for daytime naps as she will not self settle for them unless she's in the car or buggy.
I realise it's probably not the ideal way to do things... The nursery probably will give me the
look and I have no idea how I'd cope with more than one child! But it works for me for now. :)
It might work with D? I don't like leaving M to cry, but I'm happy enough passively comforting her with a silent cuddle. I guess it's a variant on the Pick Up Put Down technique..?