Is there a certain collar lead or chain to use for a great dane?

It's all about training. You can train a puppy to obey you off leash anywhere, so that the collar and leash become only something as a formality to have on in public. The breed is immaterial. We own 14 giant breed dogs and teach them to obey from when they are very small puppies. Learn all about obedience off leash training. A choker collar will not stop a dog from pulling you over if it is untrained and out of control. Harnesses will give you even less control as the dog will be stronger than you. When you have your puppy on a collar and leash, do not move if the puppy is in front of you or pulling. Change direction and stop the minute the pup tries to get ahead of you or pull. Just don't entertain being pulled along. If he pulls, you don't proceed. Sooner or later he will get the message. I use the command "back" when they try to walk ahead of me. Good luck. Google training websites.