This is a long winded way to ask what is probably a simple question with a simple answer.
I recently purchased the Copperhead as an upgrade for the Anycubic Vyper. The Vyper's stock hotend has the sort of design where the bowden tube goes all the way through the heatbreak up to the nozzle. This design raised some safety concerns regarding PTFE degradation, and so I decided to go with the Copperhead. This printer isn't on the compatibility matrix, so I took some measurements and went out on a limb. The Vyper requires that the heatsink be mounted to an arm that contains a strain gauge for auto-leveling, so using the stock heatsink (which already has the appropriate holes drilled) seemed to be the most expeditious route to safety at higher temperatures. The stock heatbreak has an outer diameter of 6mm and a cold-side length of ~17mm. The heatsink is machined to match. The Copperhead G2 heatbreak is 12.5mm long on the cold side (excluding the 0.5mm bevel on one side). As such, there is a 4.5mm gap inside the heatsink when the Copperhead heatbreak is flush-mounted with the stock heatsink. The bowden tube is inside of this gap and has an outer diameter of 4mm, which means there is space surrounding the bowden tube that is just air. I've installed this setup and after some mechanical adjustments (Z limit), everything is working.
Alignment of the PFTE tube with the heatbreak does not seem to be an issue for now. However, I wonder if the air gap inside of the heat sink can create a high-temperature zone that would allow the temperature of the PFTE tube in this air gap to approach 200C, making it unsafe for use. I would appreciate any advice or perspective that you have in this matter.