Well Howards strategy is fairly straight forward and simple. Many people have done it similarly over the decades. I think if I was to use it, i would tweak it a little.
For example: I could see where he would get wiped out whenever the VIX moves between 20 and 30, using two month out options. I would set some extra rules than those he has mentioned here. Certainly Two month out, Bull put credit spreads would have difficulty in a VIX 20 to 30 environment. When VIX starts having VIX 60, 80, 120 or even 160 days, as I´ve seen, the Bull Put Credit Spreads would not survive, nor the account.
So a rule that you quit Bull Put Credit Spreads after VIX touches 20 would be a good one. Indeed, I would further refine such a rule that Bull Put Credit Spreads would not be put on after VIX touches 18, on the second month out, as in a rollover situation. Might be chancy, and might work on the first month.
Most of Howard´s testing period both funny money and particularly cash has been below VIX 25, and even I dare say, below VIX 20. I believe right now we are at VIX 19 thereabouts.
Mind you, as the VIX rises, the Bear Call Credit Spreads become more attractive. The problem is with those two month out credit spreads. An environment of VIX 20 to 30 usually lasts 3 to 4 weeks. Above VIX 25 you should have completely shifted to Bear Call Spreads. I can see using the appropriate rollover credit spread, into the next month, provided you stick to the VIX trading rules.
The only idea of a second month as far as I can see, is to gain extra premium in a rollover, or new trade. I have a vague idea I would close out all Bull Put Credit Spreads whenever VIX hits 18. Below that is fine.