If you're doing the dragon fight most of these assholes don't know shit, 50k plus health for rexs and 700 pluss for melee plus a decent saddle and you'll lose none. Trust me its i've written it on the internet
If you have the resources, tame a titanosaur for the alpha dragon cause the titanosaur is OP and can slay the dragon. (Bring more tames like yuty and daeodons
if you need) Just be cautious about dimorphs in the battle!