They turned out really lovely. I like the blue and pink colour combination too. I love Dorset buttons because you can match them to a garment.
I have made them in the past using slices of pvc pipe, as where I live you can't get the proper rings. You can saw slices off the pipe quite easily and then use sandpaper to smooth the rough edges.
These were buttons I made for a cardigan https://www.craftster.org/forum/index.php?topic=440525.msg5334388#msg5334388
That is a great idea. I have loads of plastic tube in my stash... they make great llittle rolling pins for clay... I do love your buttons. I need to practice a bit more I think.