Hello Paul
Yes I spend hours and hours with Pamelas Glas Musterbuch, I΄m hoping she comes along, I`m sure she will know it in seconds. May be I send her a whats Ap, she said that she will help if I ask, I did΄nt want to bother her. I was at her museum a while ago, absolutely mind blowing. When you visit Hamburg you should make a appointment and bring lots of time.
If a plate means only absolutely flat, then you are right, then we deel with a bowl. For a bowl I thought it is not high enough 4cm.
Monika