well this may not be super helpful, but I recently came with my bernese puppy Sammy to spend some time visiting my parents and their nine-year-old golden, Maize. At first, Maize was NOT a fan of Sam- she'd always been an only dog, and you know, she's the boss of her house, and older, and set in her ways, and frankly has never been crazy about other dogs. But from that inauspicious start, they're now great friends, and Maize is the bigger instigator of the two of their little wrestling matches. So I don't know if you can predict easily how well two dogs will get along from a first interaction. I tend to think you'll be just fine, but I don't really know anything about a pyr personality.