Lets look an example: L 107 Call S 105 Call S 95 Put L 93 Put There is your iron condor. Lets say price breaks up adding a long cfd turns it into the following L 107 Call S 105 Put S 95 Put L 93 Put So if that's the position you want why not just keep it all in vol and forget the cfd?
Do you realise that once the Cfd kicks in, you completely changed your set-up, opinion and risk? It's another trade. I prefer to take a loss and start again with a blank sheet. Why? Because I have been there. Are you looking to eliminate all losses? Or just make them worse...? Because it must be one or the other. It could be different (maybe) if you were just delta hedging but it doesn't sound like that with Cfd's in the mix.