Grapefruit are ok on their own roots except that they will tend to be susceptible to phytophthora foot rot. So it would be important to plant in a well-drained area and keep the base of the trunk open to the air (weed control, don't plant too deep, don't mulch, etc.).
Fruit from such a tree will be at the lower end of quality -- rather dilute, but can be fairly good if quite mature.
But the big issue here -- you're in Florida. Federal and State law forbid the propagating or movement of citrus plants by any means, for any reason, unless you are a certified citrus nursery, as part of the ongoing greening and canker quarantine programs. So you'd be better off buying a tree from a licensed nursery.
