Formula and what poop should look like for 6 week old

So I’m a first time momma and my son is 6 weeks old. :) He has been formula fed since 4 days old (couldn’t breastfeed- didn’t produce enough and was really uncomfortable)... anyways he was on Similac Total Comfort since he couldn’t poop on the Similac Pro Advance. We recently found out he has reflux (been vomiting after feedings and Screaming) and possibly colic so his doc changed his formula to Similac Alimentum. He was on that and still screamed when he was burped and when he spit up. So now he’s on Zantac which helped a ton! But while on the Alimentum, he couldn’t poop and when he finically started going it was so thick and he was straining to hard to push (but his poop was not hard) so my husband and I decided to put him back on the Total Comfort (since he was pooping 2-3 a day on it.) My question is what is he poop suppose to look like? Here are 2 photos one of when he was on the Alimentum (1st photo) and the other on Total Comfort (2nd photo) . Sorry for the photos but I need to know if this is okay! (Why is the total comfort poop seedy? And is that okay?) Thank you!! ;)