I've heard of the following hedging strategies:
1. Buying outer period ATM or OTM puts with a % of credit collected.
2. Buying VIX and VXX call options
3. Offsetting with ES futures
4. Position sizing
5. Long positions creating vertical spreads - or a ratio IC.
I am sure there are others. I think spending 10% of the collected credit is a fine amount to spend, but I think you have a couple choices here.
1. Do you buy 1 closer to the money put? In my model, I'd be able to buy 1 put for every 10 puts opened (and every 50 calls opened) that is one month out, which is 8% OTM at current volatility. I could open this put each week creating a ladder. After 4 weeks of doing this, I'd have only 10 short puts opened and a ladder of various long puts at different strikes, with different expirations, all about 8% OTM. Of course, this 10% isn't really wasted, as if I wanted to go all cash, I could sell some of them back for a profit. This sort of scenario would let a black swan happen, and instead of surviving a 40% drop before a first margin call, I'd get about 58% drop before my first margin call materialized. There may be some positive short term gains that come from markets that are having a normal 5-10% correction as both the short and long puts could show gains.
2. The other choice is to go far enough OTM to buy enough coverage puts each week. We'd have to go about 15% OTM to buy these puts. If you applied the same ladder strategy, after 4 weeks, you'd have about 40 long puts for the 10 short puts that you are carrying. In this black swan event, you'd like end up with a positive net liquidation overall if you deleveraged the short puts and sold all of the long puts. I may take some time to run some simulations if the market drops 20% and VIX goes to 150% with a ladder of options like this.