Good afternoon, JACustomer. I'm sorry that Dr. John was unable to help you earlier. I hope I am able to help.
The information available to us, as Dr. John pointed out, is that Cypermethrin is toxic to dogs especially when they consume the concentrate. Once it's dry, the toxicity level is much reduced. This chemical is a pyrethrin and you can read all about pyrethrin toxicities online. Since you've done so much research on ticks, I suspect you've likely come across this information in the past. There's more information here, if you need it: http://www.vcahospitals.com/main/pet-health-information/article/animal-health/pyrethrin-pyrethroid-poisoning-in-dogs/8328
What information I can find on the chemical for dosing states that it needs to be under 1% solution, which may still be too low to kill ticks. This is something I would consider before using it.
One thing I did not see mentioned in your discussion with Dr. John is the use of a tablet, or product that works "from the inside out". As you have observed, because of their very thick coat it's hard to get topicals down to the skin. I, like you, live in an area that is densely populated with ticks and summers here are a nightmare. From basically February to November (and occasionally year round) we can expect ticks to be out en force.
Because of this, and because I do occasionally wind up with chows and other breeds with dense coats like the Akita, I have started using two products together (fleas are also an issue here, as well). The first product is Nexgard (http://www.1800petmeds.com/NexGard+Chewables-prod10356.html). This tablet is given once monthly and prevents both fleas and ticks. Because it does not work from the "outside in" you don't have to worry about 1) a densely coated pet who won't receive the benefit of the topical (2) a pet who is frequently bathed, groomed or who likes to play in water. With Nexgard, all that is entirely safe because you absolutely cannot wash it off or otherwise lessen its efficacy.
The second product is the Seresto collar: http://www.1800petmeds.com/Seresto-prod11501.html Up until now, I have never seen a flea/tick collar that has worked. Unlike many collars that don't work, this one works...and works for up to 8 months (nearly long enough to last our whole season, so we apply them March to October, personally). Because you're working with thicker coated dogs, the most effective way to use this would be to trim the hair down (not necessarily to the skin) but at least to where you could easily feel the skin when you reached down to their neck. They can also wear a regular collar on top of this collar to protect it from being pulled off. They're even slightly stretchy, so I make them tight enough to fit flush against the skin in our dogs but it makes it possible should I want to remove it for the dog to be bathed.
If you were hoping to find different information and my answer has not helped you, just let me know. I'll be happy to opt out just like Dr. John did and allow a different Expert to step in, who may have more information for you.
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