Thanks for the kind adviser.

Actually I'm trading IWM options mimic to RUT, so it's really small amount. The reason I decide to trade a small position is to put my learning into action. I read some option related documents and I feel like I can understand lots of principals and concepts but never was able to learn kind of details that are needed in actually trading.

Back to the question: it seems to me although PUT & Call calendar compensate Vega the same way; but in a down-side biased market, I was thinking Put calendar may give a slight directional advantage, then again this directional thinking maybe should be put-away in such non-directional trading set up.

PX