Hi Nancy! I have seen the sling set and it looks pretty cool. I want to get it...and get all the others slings and wraps that look so cool!! :LOL I am addicted!!
Anyway I use ring slings. I use one for both babies when they were tiny. I started this when they were about 2 wks old. They were both facing me tummy to tummy. They were small girls. 5lb7 and 5lb12 when born. So this wasn't very difficult but I did not nurse them like this when together. I never tried it. They always just fell right asleep once I put them on so I guess never really needed to. I did nurse them when wearing one however.
When got a bit bigger I'd put them each in their own sling in cradle position but down lower and to the side more so I could wear them both. Then when had more head control I'd wear each in own sling on each hip with fabric pulled up high on their back and neck for support till their head control was better.
I was also able to wear one on front and one on back with the ring slings. But I hear mei tai are much better for that. I keep wanting to get a Kozy carrier for this position!! And I also just tried a Ergo on the other day. Man was it comfy! Not as pretty but the weight is more on hips rather than shoulders. But you can only wear one baby in it. I had my 15 mos twin dd on back in an Ella Roo wrap and 2 1/2 yr old ds on front in the Ergo. And was able to bend down and change other 15 mos dd diaper on the floor!! Whew!
Hope that helps! Enjoy wearing those newborns when they come!