You can always give us a ring at the office or shoot us an e-mail to discuss your project in detail but a good rule of thumb is:
LSG-3 is good for patios and walkways with pedestrian traffic up to 8,000 lbs.
LSG-4 is good for standard cars and pickup trucks up to 40,000 lbs.
LSG-6 is good for heavy trucks and fire access up to 80,000 lbs.