This is an updated version of the cooling fan box for TAZ3 I posted previously. The update involves modifications of the holes and addition of a heat sink cooling hole. I found the heat sink cooling is a nice force cooling for the heat sink, It keeps the aluminum parts cool and it minimizes the digging-in problem which enables the printer to print with more brands of filaments.
Yes, you can tape the holes you are not using. For example you want to tape the filament cooling hole when you are not printing PLA. I will keep the Heat sink cooling open because it makes the hot-end works better.