I'd be very careful and choose the product after much consideration. I've heard mixed reviews on how safe it is. Evidently some dogs can be allergic to cedar oil, and some can apparently be overwhelmed with the scent. So choose carefully and discontinue if Marty seems to develop any weird symptoms (like itchy or swollen eyes or face).
I'm not sure how effective it is for ticks, though. I've not tried cedar oil, but other essential oil treatments I've tested have been pretty ineffective.
I know a lot of dog owners in the south are using the Seresto collars for ticks now, since Frontline has become less effective down there. They seem to be having good luck with them. Is that something you've tried with Marty?