If you use the bear trap strategy which is if you lead it into a Dino gateway that is shaped in a triangle and with a bear trap in the middle (Large Beartrap) and when it is stuck you must put a dinogate behind it to trap it and then knock out. (hope this helped and "If" I win could it be an Xbox voucher, thanks.)
When breeding two max level rexes to have a super baby, DON'T EAT THE EGG!!!! I've done this twice on accident(meaning to drop it) and each time it takes me a couple seconds to register wtf I just did and then I have to wait to mate again. Sad day. Weekend ruined. Great way to start off the new year! Lol
The best way for me is to get dino gate ways and place them in a circle but leave one hole open to lead the rex in it so get a tribe mate and send him in with the rex trying to eat him and once it's in place the last one behind it
Be a safe distance from the Rex then strike! When you knock it out make sure you have enough narcotics (if not make sure you have a raptor to get home quickly!). It’s easiest to hit it with a long neck rifle in my opinion
Rex baby consumes meat at about 1 meat per 50 seconds. Each meat gives about 50 food, with a food drain of 1 food point per second. So.. 1 meat = 50 seconds of feed. 1 stack of meat is 1000 seconds/16 min. A stack of meat takes 12hrs to full spoil. So.. on 1x, at 6% maturity, a baby rex can be left to fend its own till juvi... this is even with a 2 hr safeguard to be very safe. Honestly... 5% would work also. Hope these statistics help!
Create a 3x3 mobile taming pen 3 walls high on a raft with a Dino gateway on one side and ramps on the other. Use a flyer to lead it up the ramp into the pen then move it to a safe area to tame. I got 2 150s without a single issue.