Never tried Coolababies so can't advise. I can second that petite d'sous and Easy Peasy hemp boosters make fabulous inserts for pockets though. Max is a heavy-wetter and that combo has been the only one that has worked for him.
How often are you changing the nappy? Could be you need to change more regularly if LO is a heavy-wetter. Also check out the classifieds for other pockets nappies. Bum Genius and Tots Bots Easyfits V2 have worked great for us.
There is also the reviews section which could help you decide what other nappies to try