Printed as-is in Gembird PETG (Dutch manufacturer) at 235°C with 80°C heated bed, "Everyday" brand (generic) hairspray on a 300x300 mirror directly on top of the aluminium plate. 50 mm/s worked fine for me, YMMV. Has a 2° taper on the part that goes inside the sensor housing, and fits in just fine at 100% on my printer. It's not loose, but it is easy to remove, so you may want to oversize to 101% or 102% to make it a tighter fit.
The reason the actual extruder parts aren't shown in the picture is because, as you can see in the second picture, it's mounted directly above my hot end to turn the printer into a makeshift direct drive-alike. The reason it's not color coordinated is because I was testing different filaments and wasn't sure how well this would work yet.
Loaded DoogieLabs' STL file into Fusion 360, turned off the design history, converted the mesh into a BRep to make it easier to work with, turned design history back on, and drew a little lid on top of the existing object. First iteration didn't have enough of a protrusion on the inside and would just pop off, second version fits much better.