two dogs = two vet bills, two dog training costs, two dogs on walks, two of everything. you have to do separate training time and play time with YOU so that the dog bonds to you not the other dog.. since your female doesnt really like other females then a male is the way to go. group training courses are good to as they work on any issues your dog might have with other strange dogs. i always do group training so that my dog is used to other dogs but thats just me.
size only matters if one gets hurt, but any size dog can get hurt during play time. i have a 55 lb, a 60 lb and a 38 lb dog here , plus on alternating weekends an 80 lb dog. the 38 lb is monitored during play as she is 17. the other dogs ages are 3 , 11, and 9 years old. they all play good together (except my 11 yr old male he cant play with more then one dog at once ) but otherwise they all play and get along good..
as long as you are ready for two dogs and financially can handle it there is nothing wrong with 2 dogs as long as your female wants a live in playmate.....
lol on her being breed specific.. if she prefers her own kind then get her own kind.. some dogs play rough,some play gentle..