Tobi_444
Roshi can’t summon the 4 tails in his full tailed beast form. He can only wear a chakra cloak, much less literally stand on top of his tailed beast’s head. If the tailed beast could manifest in such a manner, he would have picked up Roshi, chucked him like a bag of potatoes, and ran off into the sunset. He hates humans and doesn’t like being enslaved. I’m not sure why you’re trying to make Roshi like Killer Bee, but he’s definitely not a perfect Jinchuriki.