With thick hair that mats, you may need to keep it trimmed in those areas to prevent it. Cornstarch and working it out with your fingers may help but Mandie would never sit still for me while I tried to do that.
Detanglers are good to spray directly on a tangle - most come out in a line of fluid and not a misty spray. But daily, I would highly recommend Madan's Brilliant Sheen Spray - it is great for daily grooming - it is a fine mist spray. I got mine from Jenny here:
toplinepet.com 