Greetings:
Instead of violating that Cherry Aery side cover, consider a better shock. I had the same issue when I installed the LeoVinci 4447 - it'd kiss the cover and got smeared with red plastic rub-off.
DayWot sold me a 270 (the blue one) Taiwanese shock, and the difference was like night-and-day! No more panel contact even at full bump, and the ride is just
much better. I no longer scrape the centerstand coming around corners. Saves on underwear laundering.
If you chop that panel, you can never go back. Why do it?