Yeah, great idea - so your delta will decrease (because of the short gamma) as the underlying sells off which is when you need short delta the most
This is a bit of a long post but I had to lay some ground work.
I think this is a great point to bring up because I would argue that in the long term, using short calls as a negative delta adjuster will beat out short stock or short futures(static delta) as the better approach, as long as the IVR is high enough (and it usually is after a large selloff).
Why would I think that? First, I will take the position that nobody knows anything. We can all prognosticate about future market movements but we don't know. From that starting point, then we have to look at the fact that we are building strategies for the long term game where there are many outcomes besides just a continued drop in price. You mention a continued selloff, but anywhere from a sideways consolidation all the way up to a face-melter rally are also possibilities.
I like to keep my portfolio delta's negative most of the time as downside protection from the unexpected plunge. If we get the plunge and my delta's shoot way up, say from -100 to 100. I can either put on static delta's by simply selling 100-200 shares of SPY, or I can put on a couple short calls and try to get somewhere in that same range.
Let's say I am going with 45 DTE options, if the market goes sideways for the next month I will have both protected my portfolio with the extra negative delta's and the hedge will have yielded 1-2% portfolio profit. Pretty nice. It's the hedge that keeps on giving.
In a different scenario, if the markets were to have a face melter rally, depending on my strikes and some other factors, I will likely take a small loss at first but if price stays within my strike I will still make full 1-2% profit. If the rally keeps going I will roll my call up and out to reduce delta and gamma risk on the position.
With the static delta's, if the market goes sideways then the portfolio protection was there but it yielded me no profit, and likely cost me something to hold the short position.
In a different scenario, if the markets have a face melter rally then this hedge is really going to hurt me. We will use a recent, real-life example. When the QQQ's decided to rally 4.5% on Friday, my 42 DTE call incurred a loss of 0.9% of my total account size. If I would have had static delta's then my hedge loss would have been closer to 3-4% of my total account size, ouch.
That call option I had sold originally had 1% of profit in extrinsic value, and it now has 2%. As long as price stays below 161 by expiry, I will still make full profit on it. The 1% loss will eventually swing to a 1% gain. A static hedge on the other hand would sit and hold the full loss, incrue cost to hold, and pose serious upside risk of the stock market were to keep rallying. If the hedge is taken off then I lock in that 3-4% loss, not cool.
That means the only way a static delta hedge comes out ahead of dynamic is if there is another large drop. Even in the case of a drop, a static hedge doesn't necessarily win. If the market drops and then recovers or does a side-ways downwards drift, or even if it drops but it takes a few months, the option will likely come out ahead. Even if there is a follow up plunge, the short call is not impotent, if it is actively rolled down it will still do a decent job hedging losses, just not as good as static short delta's.
The question then is this, are there enough epic plunge's to justify static delta's over dynamic. I think looking at the history of plunges, the short prem. is the best approach. Many plunges would have actually netted a profit due to how much IV overstated RV. Also many of the plunges were followed by mega rallies (like the one that happened Dec 26 and the one that happened last Friday), any static delta hedge's would have accrued huge losses, and likely more than you would be able to justify for that once in a great while mega plunge, like in 08'.
I know this can be a touchy subject but I have looked at a lot of studies and lived enough of these to feel that short prem wins in the long-term game.