NATO uses specific standards, primarily guided by STANAG 3726 and related U.S. military standards like MIL-STD-8591, for “bail (portal) lugs” used to suspend munitions from aircraft racks. The key dimension for compatibility is the lug spacing, not the individual lug's size. Common NATO/military lug spacings include:

• 14 inches (356 mm): Used for 250 lb and 500 lb class stores, such as the GBU-38.
• 30 inches (762 mm): Used for 1,000 lb and 2,000 lb class stores, such as the GBU-31.

The lugs themselves are robust to handle the weight and forces involved. A specific embodiment in a patent described one such lug as approximately 4 inches wide, 6 inches long, and 3 inches deep.

The arma dynamic pylon system used a “proxy object” placed in the model to to located any weapons and racks you select. BIS decided to do things in a very odd and in my opinion illogical way. Their way means you need to make a custom pylon for each plane.

My way has the proxy at the mid point between the aircraft lugs.