After the PTFE tube scuffed up the acrylic top panel on my Trident, I was determined to avoid similar issues on my Voron 0.2. With the correct length of tubing and umbilical wiring, the top panel of the v0.2 is untouched, but the back panel of the tophat isn't so fortunate.
This simple bar slots into the tophat extrusions and is secured by 2x M3x6 BHCS and corresponding M3 nuts. Due to friction fit, the bolts aren't really even necessary if the extrusion spacing is exactly 200mm.
I mounted mine about halfway up the tophat and found that a single bar prevented any contact of the tube and wire with the back panel.
Since I designed this, I've added Maple Leaf Makers' URBI (https://github.com/MapleLeafMakers/V0_Upper_Rear_Bowden_Inlet) to my printer, which on its own seems to prevent contact between the PTFE tube and the tophat panel, but the umbilical wiring still touches when the printhead is near the back of the bed so the ‘backsplash’ stays.
The author marked this model as their own original creation.