Good question. My experience shorting, is that "poor quality" stocks, can be expensive,as they sometimes have "good" news that can bump the value up a lot short term.
I have found the qqq and spy much safer to short, and more predictable. Obviously, a month ago shorting the qqq was a better bet,but now tech is back in favor and if we keep going up, then one will get burned badly with a short in qqq.
I want to short, but the market looks like it wants to keep going up. Probably should be fully short right now,but have lost too much money shorting this kind of market.