I had some thoughts on dynamic tax rates depending on how desirable a product or service is.

Then can do standard formulas like, will operations continue if the power is out, internet, smart phones, running water, phone lines, payment processing, etc, how long will service be down 1-3 days, weeks, months etc

If your store can't immediately switch to cash apply some modest tax increase. If people can't buy food for more than a week the extra tax is high. You might want to buy gas lamps and a "home" battery.