Its very easy actually. I just did my first on a cheapy full size kayfun i bought, one channel was completely choked by the colar, only one channel was even open lol. Just drill the original channel a little deeper/wider try it out and go from there, a little at a time.
The kayfun mini's dont have enough clearance between the wall of the tank and the collar of the wick/wire housing. Even if you drill the channels i'm wondering if you will still have issues...i did read the pmma tanks give an extra mm of clearance though so keep trying, good luck! The only reason i know is because i wanted one so i researched it.