i have a friend with a 200 lb great dane and a 130 lb great dane...she also breeds her female shih and her female chi. danes and mastiffs are some of the most gentle dogs in the world. she has never had a problem ONE with her pups or adults being around the danes. I plan on raising danes in a couple of years and don't worry one bit about them being around my maggie. yes, maggie is a tad bigger than what she is looking for (maggie is currently 5 lbs at 6 months old) but i have had danes my whole life and knw how gentle they are. so I don't worry. I put danes and mastiffs in the same category on a lot of things,..they have the same temperment and are both very large. yes, accidents CAN happen but a responsible owner would know their large dog well enough to know what to look for. I have seen many posts about pits and yorkies and know how touchy this subject is...pits are a TOTALLY different animal than a mastiff so let's not start that subject again
plus...if she is getting the mastiff first, the mastiff will be a year old next spring when she is looking to get a yorkie, by then she will know if a yorkie would do well in her home with her mastiff.
I am curious tho....will the mastiff be indoors or out?