srothstein has discussed this in previous threads, but it has been a while. It seems to be very much a "you'll beat the rap but not the ride" situation. Here's how I understand it.
The 51% restriction for carrying is a PC §46.035 restriction, which all apply to the
premises.
Penal Code Sec. 46.035. UNLAWFUL CARRYING OF HANDGUN BY LICENSE HOLDER.
(b) A license holder commits an offense if the license holder intentionally, knowingly, or recklessly carries a handgun under the authority of Subchapter H, Chapter 411, Government Code, regardless of whether the handgun is concealed, on or about the license holder's person:
(1) on the premises of a business that has a permit or license issued under Chapter 25, 28, 32, 69, or 74, Alcoholic Beverage Code, if the business derives 51 percent or more of its income from the sale or service of alcoholic beverages for on-premises consumption, as determined by the Texas Alcoholic Beverage Commission under Section 104.06, Alcoholic Beverage Code;
(f) In this section:
(3) "Premises" means a building or a portion of a building. The term does not include any public or private driveway, street, sidewalk or walkway, parking lot, parking garage, or other parking area.
This is different from the definition of premises in the Alcoholic Beverage Code, which delineates where the establishement can serve alcohol. There, premises is defined as follows:
Alcoholic Beverage Code Sec. 11.49. PREMISES DEFINED; DESIGNATION OF LICENSED PREMISES.
(a) In this code, "premises" means the grounds and all buildings, vehicles, and appurtenances pertaining to the grounds, including any adjacent premises if they are directly or indirectly under the control of the same person.
Now the Penal Code definition is what matters for CHLs, but it is a distinction that many officers aren't likely to be aware of.