If i wanted to raise the levels of my bottom teeth, how little can they raise it with bonding.

Very little: But that may not be the best option for you. If your teeth have been worn away from grinding, then the bonding will also be worn away or broken off rather quickly. You may be a candidate for porcelain restorations. Speak to your dentist.

Bite plate: Before "raising" the teeth, try a bite plate appliance first to see if your body can tolerate the overall change in your bite and it's effects on your jaw joints and skeleto-muscular complex.

Needs to be seen: It depends on which teeth, how many teeth, where and how much. It's also important to know why you want them "raised"? Is it due to wear, poor occlusion (bite), fracture, malformed teeth, etc? We really can't give you a good answer to your question without actually examining you. Consult with your own dentist who can give you a complete and thorough answer.