I can not reply on behalf of Des, But 231 P flys on global indexes when skew is steep have been amazing for me. It allows you to trade higher moments and be bi-modal to certain greeks (long theta and gamma). When you trade OTM 231 P flies you need a better model than BS to figure out your hedge ratio as I have learned this the hard way. Maybe Des can share his insight on that.
I'm going to disagree: noting that this "OTM 231 P 'fly'" is a vertical put spread nested in front of a put butterfly, I have had any number of nested positions stacked up from responses to a ranging market. I monitor them with a tailored BSM PDE set-up that uses (IB-TWS) platform-provided portfolio greeks as inputs, and manages things just fine. (More than 'just fine' -- the accuracy continually impresses me, on a nearly daily basis.) So, if you have an issue, I'd certainly be interested in a deeper view -- if only for my own purposes.
Why is bull the only direction you consider. Anyone can be profitable buying stocks, futures and calls regularly in a bull environment, you can almost do it blindly without skill or knowledge and believe you have a system. But bear markets are also directional. Also many stocks go down as well as up. Actually, bull or bear is irrelevant unless you are picking stocks that are just proxies for the market and that goes back to what I said above. If you only trade based on bull or bear markets then you are not really trading, just piggy backing. It is important to know the difference.
This confidence doesn't reconcile with this defferece: Surely there's some pithy, cursory answer you can give us.
there was a thread a couple weeks ago that went into great detail on why a couple guys here trade 231 flies with great success. I'll see if I can find it.
It's analogous to going on a firearms forum and asking if anyone owns an AR15. I dunno, a dozen threads on the subject, at least? Help me out here; WTF is defferece?
A 231 p fly, is not the same as a 121 p fly with a "vertical stunk". Try building it on your platform and you will see it is not the same. Bsm does not price skew correctly, your Greeks are all perpetually confused. A stochastic/ local vol model might help you with your delta hedges.
The idea behind the 231/132 is to exploit skew while maintaining (terminal) PNL symmetry. NOT the BWB. You guys gotta block McGinnis--he is literally too dumb to debate. It's like attempting to teach calcII to your dog.