Not tried, but when I had something similar to a 3020, though UK sourced, I found chasing stiffening and accuracy when engraving (which is no easy thing to do well unless your machine is stiff!) long winded and ultimately futile. But!, walk that path. Try it (why PTFE?, out of interest?) and report back. Keep an eye on Z deflection across X/Y travel as well as being aware of possible XY deflection. Turning your conversation around you have a perfect opportunity during lockdown exploring the limits of your machine.