I'd personally recommend to tame these on a weekend during a 2x taming event. A 150 will take you one and a half hours with megalasaurous kibble. It's torpor rate is really high as well. A 150 will drain torpor in about 15 mins. So have LOTS of narcotic on hand. To knock out build a simple dino gate and doorway trap or get yourself up high on a ledge to shoot down. Avoid being attacked on foot because it will hurt.