I'd say that if they are still young and fresh it doesn't really matter which one you train. Train the one which is lower. Only once you get get to a certain level you wanna be training only JS cuz many people argue that training JR beyond, say tremendous or wondrous is not at all cost efficient. So train the one which is lower, and once both of them become quite high like say prolific give a bias to JS. Also it depends on the potential of course. If the potential is low then I'd say give a bias towards JS earlier say, when both reach strong. Just my opinion. Hope it helped!
H
"Falling in love is not at all the most stupid thing that people do but gravitation cannot be held responsible for it."