Hi, I am using a different heat-break then stock which doesn't go all the way to the top of the cold side of the extruder. I needed to add a tube onto the bottom of the original part to fill the gap left. this allows me to print with flexible PVA. As with the origional, you will need to clearance the hole with a 2mm drill or equivalent.

I used Meshmixer to add the part needed. This is my first successful modification of an STL file so hurray for me. lol.