A dwarf burm is still a pretty rare snake, although they do exist. To my knowledge, Bob Clark was the first to work with them and quickly discovered that pure dwarf animals seemed to display a very hostile nature with lots of musking. Now, it's been a while since the original imports were brought in so you have normal blood mixed in to different extents. As far as care, it's the same (I keep my Burm at 80-92 gradient with a 60% humidity) with exception to prey size obviously.
Im of the opinion however that if you're going to dabble in large constrictors, just get a full blood, normal male. If a dwarf exists, go for it, but then when you add normal burm genetics back into the dwarf genetics as most of these animals are....you could still end up with an animal that is going to get pretty close in size to a normal burm anyways. Get the dwarf but also accept the possibility that you could have a 40-90lb animal on your hands even if you get a male. It's the same concept with retics....dwarf genetics definately keep sizes down, but you're not getting a species known to stay small regardless of dwarf percentage.
I guarantee you'll have Sauzo or someone else give you a further rundown on the dwarf retic side of your question shortly...I won't talk out my butt about them as I don't own one however lol.