[SPACE] Rules considering Lagrange Points in Advanced Worldbuilding

[Sabersonic]

For my first thread on this board, I have a few inquiries related to the Advanced Worldbuilding in the creation of a customized star systems, or rather the lack of information for details that I require. Mainly Lagrangian/Liberation/Trojan points.

For Lagrangian Points subject, well I wanted to create a habitable moon of a Gas Giant that had Co-Orbital Trojan Moons along its orbit at the L4 and L5 locations after recalling and looking up information on natural occurring Trojan Moons of the Saturnian Moons Tethys and Dione as explained in this Wikipedia Article. Since my hardcover copy of GURPS Space 4th Edition did not have the information I sought, I attempted to search for the information through the forum. Although I have found some interesting notes about Lagrange Points such as

Originally Posted by dataweaver

(maximum mass for satellite with stable trojan points = 4% of primary's mass)

Originally Posted by Brett

The L4 and L5 points are only stable if the ratio of the masses of the two stars is greater than about 25.

However, I did not find the answers to my questions in determining if a Planet-Moon system could have Lagrangian Points or not and the maximum mass/moon type/moonlet that could occupy that zone. Is there a suggested dice formula to determine if such a system could even have Lagrangian points if they meet certain requirements or do I just dictate that those two bodies have those points and leave it as that?