For a Cancer Ascendant, Aquarius falls in the 8th house. Saturn and Rahu are co-rulers of this house, and since it is a Mooltrikona sign, Saturn becomes the primary ruler. In a video, Sir explained that if any planet rules the 8th house, one should consider wearing that planet’s gemstone. ( sun (0 ),moon (5), mars (27) , venus (24)) in 8th house ..
Now, my confusion is in this specific chart: Saturn (8th lord) is placed in the 4th house, retrograde, in Swati Nakshatra. Rahu (the co-ruler) is placed in the 12th house. In this case, which gemstone should be suggested? How can I properly judge the strength of these planets—especially Rahu, since in JHora we cannot directly see Rahu’s strength?