John,
If you follow these threads on the CTM IC back to January you can glean more of the thought process that goes into trading the CTM but I will summarize some of them quickly here. From your email I think you already "get" the main reason to trade this CTM from my viewpoint, less/more controllable risk. Note what Vikas and others have stated there really is no "right or wrong" way to do this. There are however, some basic premises that I go into the trade with each month. I know that if I collect about 40% of the spread width in premium: $4 on a $10 RUT spread I have the ability to make certain adjustments if the trade goes against me. The most basic way to adjust/protect the CTM if your trade is going against you is to BTC the endangered short vertical when the index reaches that short or actually trades past it a little. If you look at your TOS option pricing for verticals you will see that the ATM verticals trade for about $5, give or take a little. If you do nothing after collecting your initial credits but sit and wait for the index to attack your short verticals you can always pull the trigger and pay the $5 to buy back the endangered vertical. You took in $4, paid $5 to close so you are down $1 with no more risk on one side. Note you still have risk in the other direction and you will have to decide if you want to BTC that side based on cost, time to expiration etc. These are all round numbers but you get the idea.
Your next step will be to decide if you want to sell another vertical further out to bring back in some credit and eliminate your $1 loss zone.
Note that to BTC your short vertical for $5 is usually a last resort type of adjustment. It often pays to close your trades early for a profit, make other adjustments like buying calendars, verticals, butterflys, roll out or up etc. I am of the school that believes that you try and make as few adjustments as possible. When you put the trade on you have a certain probability of success, if you sell your IC for $4 you have a 60% probability. If you leg in and get a wider spread width and still get $4 premium you have a higher probability (you can estimate probability of your legged in verticals by pricing them as an IC, say they are only worth $3 as an IC, that would give you a 70% probability). Generally when you are short premium you want to delay/minimize adjustments to take advantage of your probablity and time decay.
As others have stated you really need to have a plan of what you are going to do when your position is threatened because as we saw this week crazy things do happen and your position will be threatened. Up 300 Dow points on Thursday; down 400 on Friday and we are trying to trade a market neutral strategy???? Are we crazy????
Time will tell on the crazy part but if you control your risk and manage your money properly you can make money trading. No matter what trading strategy you use you have to ask yourself what is the max loss I can stomach/afford? What is your personal burn rate before you go out of business? Adjust your trade size and portfolio risk accordingly. As an old friend of mine kindly told me once when I was trying something pretty dumb and risky; "People in small boats should stay close to shore". I still use my friends advice to temper my "enthusiasm" when I get a little ahead of myself.
Happy sailing!
Mike






