Think about this guys. If you start with thicker walls say 3/8 of an inch then when you sand to blend and smooth the rings together then you do not have the worry of sanding thru the side ... I have done this several times... some of the bowls the sides are so thin you can almost see thru them. The absolutely hardest part is dust control when sanding. You will be creating a ton of fine sawdust so please wear a mask. After a while you can get to the point that after the glue dries you can rough shape and blend the bowl in less than an hour most times, of course the fine hand sanding will take a bit longer. Sand and shape the inside 1st then glue the bottom on and then shape the outside. The goal here is to get a uniform wall thickness as well as shape. Your 1st bowl makes a great rainy day project
DW