The recommended quantity of pellets is 1/4 cup per 5 pounds of body weight per day. So if your rabbit is a large breed (10 pounds or so) he should be getting 1/2 cup of pellets a day.
The most important component of a rabbit’s diet is hay. They should have unlimited grass hay such as Timothy or orchard grass, not alfalfa hay. They should also eat leafy green vegetables, and not a lot of fruit since that contains too much sugar.
Here is one list of recommended vegetables. If your rabbit is not used to eating veggies, you should very slowly introduce them into his diet.
Carrot tops
Cilantro
Beet tops
Swiss chard
Dandelion greens and flowers (no chemicals or pesticides)
Parsley
Clover
Kale
Cabbage
Collards
Broccoli – including leaves
Escarole
Carrot
Romaine lettuce (no iceberg lettuce)
Brussel sprouts
Endive
Radicchio
Mint leaves
Bok Choy
I would be concerned about letting Tobey run around in your garden. Predators can come out of nowhere to attack them, even if you are close by, and rabbits can get worms from eating grass or other vegetation that dogs or other animals may have used the bathroom on. Plus there may be some plants in your garden or yard that aren’t good for rabbits to eat.