Few different ways:
1. Cut the middle and weld the extention
2. Cut the wood slab in Home Depot of desired width and thickness to match the base of the stands
3. You can order granite slabs of the same size(or elegantly waf-compatible larger) of desired thicknes from the local monument shop. It may look silly, but will work. The owner would probably be happy to create something for alive:-)
1. Cut the middle and weld the extention
2. Cut the wood slab in Home Depot of desired width and thickness to match the base of the stands
3. You can order granite slabs of the same size(or elegantly waf-compatible larger) of desired thicknes from the local monument shop. It may look silly, but will work. The owner would probably be happy to create something for alive:-)