Congratulations on the cute new addition to your family!
Samantha is smiling down with her approval from the Rainbow Bridge.
Since Samantha was an only cat I was able to free feed her canned & dry food, now that I have two cats I can't free feed them because Milly would eat it all and Izzy wouldn't get any! I portion out wet and dry food for them for two meals and a couple of snacks/treats. I wouldn't leave the wet food down for more than a few hours especially if the weather is warm, cats tend to turn up their noses if the food isn't fresh enough.
Has Patches been to the vet's yet for a checkup & shots? They will have feeding advice for you & once you know his weight it will be easier to figure out the serving sizes on the cat food labels.
Please post more photos of the little Mini Moo Cow Kitty.
He is just too cute!