PZ, I used a shield with my first son for 5 months. My initial CHN was a bit like yours she made me scared that I was under feeding my child, I went to a LC who did get him to latch but my goodness it took forever (that was at 6 weeks) I went home still trying to not use the shield but my poor little man just couldn't latch for a variety of reasons, I'm flat, he had short tongue etc. By midnight he was beside himself I got the shield out and he was a happy little camper. I then started seeing another CHN and she was very supportive, and said the stress of me worrying about trying to get him off the shield was probably more likely to dry up my milk than the shield itself.

Anyway my supply didn't decrease he was putting on good amounts of weight, he probably took a bit longer to feed but being my firstborn that didn't worry me as I didn't have other children to tend to. I also used to offer a top up before he went to back to bed which he always took. At around 5 and a half months he started pulling the shield off whilst he was feeding that got a bit tiresome, especially out in public when this baby would be waving a shield around. So I decided it was time to try again and he started latching no problems and was breastfed til 14 months. I think being older his mouth was bigger and tongue had grown and he just attached better. If I hadn't used the shield he would have been FF from about 6 weeks of age, so for me the shield was the difference between breastfeeding and not.