That's lovely! I'm sure you are not leaving things where the live kitty can come across them any more. Having work in progress broken really hurts. And the piggy mug was fantastic. You will still raise lots of money for the animals.
The formula is to find a height that lets you keep your hands above your waist when working. Bend your arms with your elbows at your side until your hand are parallel to the floor. That should be a good height to start with. If you have a kitchen counter that you like you can use that height. You can always use chocks to adjust the height, or make a stand for a wedging bat or work board. I made one out of 3/4" pvc pipe for a very tall cook to put his cutting board on.
If the table is too tall make a step out of plywood that is the right height for comfort. Be sure to put nonslip tape on the top! Most step stools will be too tall and will have a tendency to slip when you lean over the bench.
These are the backbone of my professional life. The perfed trays are pretty lightweight. You would be better off cutting plywood to fit the rack. You could put some wire grating on top for better air movement, or wrap the boards in canvas. The useable area is about 2" narrower than the rack if you are doing anything taller than the spaces between shelves. They are available with different shelf spacing, so think about the size of the stuff you want to store/dry. The zippered vinyl covers are good at holding moisture-I used them as makeshift proofing racks by adding a pot of boiling water at the bottom with my product at the top. If you keep your wares about a foot from the bottom of the rack you can put in a water pan underneath and it should hold enough moisture to keep things leather hard for a while. You will have to experiment with your local humidity. Get the heavy duty ones and they will last for a very long time. Be nice to the casters or they will get tricky to steer and kind of jumpy, and that could mean stuff falling over or cracking.