Good luck. Short selling is the hardest part of the investing business. I agree TSLA is ridiculously priced but things can get more ridiculous before the other shoe drops. Hopefully you have a plan if the stock rises rapidly against you.
I do not bet against companies often especially during a raging bull market but when I do I choose to use put options to limit risk.
I use certificates (warrants) that are also limiting risks. And I use a limited leverage, actually 1,6x (K. O. by 497 USD).