What is the heaviest weight this can hold and what r it’s dimensions?

Thank you for your question. Our edge glued panels are made with high quality wood glue and are precision cut to ensure good glue contact and bonding with the individual pieces. However, they are not structural components and we do not load test our edge glued panels. There are many installation options, and load capacity is based on the mounting brackets or surface the panels are mounted on. We recommend using high quality brackets and mounting hardware tested by the hardware manufacturer for installation.