I've had subtle improvements with Leatherique on my Dakota seats, but it's been a while. When I did use it, I paid particular attention to the stitching, particularly at the bolsters of sports seats, for better horizontal penetration.
I agree that one doesn't get as much value from this product on Dakota, compared to when using it on other seats. I think the fastest absorption I've seen with this oil was on a LS400. It was faster than a Bounty paper towel commercial. (I'm sure this attribute is also dependent on the condition, but it was pretty remarkable to me.)
Regarding my opinion about the Optimum PP being smelly, I recently read someone else saying that it really is subtle, maybe like nothing. Now I suspect that the formula must have changed since I bought my bottle a couple of years ago, or whenever it was. I think my APC and Sonax FE might smell less offensive, though maybe not as as bad as my degreaser(s). Maybe I'll shoot an email, eventually, but for now, it's hard for me to bust out whatever is remaining. Not a joke, when I used PP extensively on any given car, I'd leave all the windows down, and all the doors open in the garage at least overnight, if not longer. That smelly!