It's just a case of lots of practice, your CS will give incredibly fine detail once you get used to it, I don't know how familiar you are with trigger technique or how much experience you have but when you push down for air, the amount you pull back for paint will determine your paint to air ratio, when you do pull back a space opens between the tip of the needle and the inside of the nozzle, the space increases as you pull back, the trick is to pull back just enough for paint to actually start coming out, this is the point where you will see just how fine you can get, I now use side feed models because it meant that the top of the brush is unhindered and I can use the underside of the first knuckle of my trigger finger instead of the tip, this gives me more control and dispenses with the need for the dreaded death grip,
, gravity feeds don't allow me to do this although a siphon feed would, why not just mess around practicing some very small dots and lines to get your finger used to it, most of do still do that for short while at the start of each session, it gives muscle memory a poke and and lets you know that brush is in good order before risking ruining your work, once you get to grips with your brush you'll probably decide that may not need another brush, but if you do buy another brush later you discover that what you can do already is even easier.
Messing around with reduction and pressure will obviously play a part in the above practice too, so keep that in mind, and ask if your not sure about anything.
Straight after I advised the Iwata HP-B above I actually ordered the side feed version of the same brush just because I couldn't handle the thought of you having one and not me,