Halo sleep sack?

elduroq9

I want to start getting my two week old to sleep in his bassinet, but I won't unless he's swaddled in some way. Every time I try swaddlers him he breaks his arms free, so I'm pretty sure the sleep sacks will be good for us. However, I can't decide if I should go with the 6 to 12 lb size or 13 to 18 lb size. My LO is only 7.2 right now, so would  the 13 lb be WAY too big? Im not sure how long it will be before he gets up to 12 lbs