You don't want to cut the barbules and instead get a feather that fits what you want. However the smaller hackles thin wide get more costly with the more narrow because then your mmostly dealing with hackle on capes closer to dry fly hackle. Not that this is a bad thing because you get a lot of feathers off of a cape like that. This not the cape, but instead is the soft hackle of this bird. The cape has longer and thinner feathers which will make the collar shorter, but it wouldn't have the chart base with black tips either. You can pick smaller thinner soft hackle to tie on a jig, but there are not near as many thin ones as there are wider ones. It all comes down to what look you want.

also forgot to mention that the more narrow the hackle the stiffer it is too. This is why the very thing dry fly hackle is for dry flies and will not soake up a lot of water making it sink. These are not for that kind of tie.

oh and this is why they make hackle gauges, so you can make the hackle fit the hook size which is important in fly tying. Using soft hackle is not as critical on size like I am using it. It's not going to stand out like this after it's wet either.