I wouldn't be as worried about every day and a half as long as he is not straining when he goes poo and it's not too hard. That's what I would go by and not worry so much if it's been a little longer than a day. Mine usually go once a day but sometimes they might make it a day and a half and I don't really worry about it. As far as gas.... not really sure. You don't give them any treats or things like veggies do you? Mine have not experienced that and even when they go poop it does not smell as bad as it used to with kibble unless they try something new and have a little tummy upset and diarhea - then it smells bad.
Here are some sites I have found helpful:
Jane Anderson's Raw Learning Site RawChat : Raw Chat
There are others out there, even here on YT who know way more than I do about raw feeding. I'm still learning myself.
good luck! Love to hear from other raw feeders!