woombie lovers please come in

buskey2011

I saw a post about the woombie and I checked out the site but not sure which one to get. my ds is 12 kbs and he like his arms free however he has colic and he wakes himself up with the startle reflux  would you do the houdini or the convertible? how do the sizes run? would you go up a size or do their sizes run to a true fit? I am going to purchase a eco doughnut while their on sale cheaper than amazon! hopefully in the doughnut we can elimate him needing the boppy to sleep. i know the boppy shouldnt be used to sleep but this is the only way he will sleep and dr okd it. TIA