paks have seen are generally sold grafted, but may have seen them being grown on their own roots. Have never tried airlayers on paks so not really sure.
they take to grafting easily though, especially in areas with mild summers, and will easily graft onto albas
you may refer to this superb thread for ‘hard-core’ info
almost certain you could grow non-astringent simmons in your area. Perhaps more resilient to cold weather than paks. It is worth delving into if you want a low maintenance fruit tree.