Enfamil AR to help with weight gain

Hi everyone! Our ped recommended that we switch our EFF 16 week old to Enfamil AR to help with spit up and subsequently help with weight gain. I’ve read horror stories about it causing bad gas/constipation though so I’m trying to weigh the advantages and disadvantages. My baby definitely spits up frequently but I’m trying to determine if it’s actually enough to affect weight gain. He spits up after every bottle and even for a couple hours afterwards during play and tummy time but I know it can look like more than it actually is.

For those of you with babies with reflux, how would you quantify the amount of spit up you experienced and did it affect your baby’s weight gain? Did you switch them to a rice formula to help?