If there is no significant difference in smell between the primary and tranny lubes, you can get an ultraviolet dye from your auto parts store. Teh kit usually comes with a UV flashlight. Put the dye in one or the other hole, clean up the area, ride a bit, and check for glowing oil. You will know from whence it comes pretty quick.
Just know that the repair operation does not vary too much, one way or the other. Your inner primary will need to be pulled to get at a seal leak, from any one of the following sources: starter shaft, clutch shaft into the primary, sprocket shaft from the tranny. Regardless of source, once in there, I would replace the seals in all 3 places, but, that is just me. Once the big part is done (inner primary removal), seals are small potatoes.
Before you go too far, just make sure that the tranny is not puking out the breather tube at the top, if your model has one. I know on my RKC, such a source can appear to be a leaky seal, since it drips from a similar location.
Enjoy,
Rich P