Use an argy trap! I was able to tame 2 lvl 150s with one. 4 stone gateways placed in a row with gates at either end once you have got the rhino in. Make sure you have a beast to protect it in case of things like rexes and sabers while its knocked out. They're so easy to tame and are absolutely brilliant once tamed.
Ez tame even for early game , just use 4 billboards, put around rhino when still unaggro and then when the rhino is trapped with the billaboards just start shooting tranqs . ( Can use wooden billaboards)