I have seen where some ask that they not look like bibs but rather a fun shirt.
You can take a real shirt, sew the front button area closed. Then cut off the shirt from the shoulders down around the sleeves. The collar is split in the back and that is where the fastener goes. Line them from the neck down with terry cloth, etc.
Just something to try and maintain some dignity . You can google the images and get some other ideas and directions.