VIX--the third dimension of monitoring the market

The market was pretty nervous today, but didn't seem too panicky. I was wishing I had been a little less demanding on closing out my bear VIX spread.  I have a GTC order in with a debit of .10 that probably came within a few cents of filling a few days ago.  If I had settled for .15 I would have been out with 66% of my maximum profits.  Then I could have gotten back in at least a credit of .30.  Oh well, it is always so easy in retrospect.

  I like to monitor the minute by minute intra-day charts of  SPY, VIX, and VXX.   It feels like the volatility indicators add a third dimension of visibility into the market.  Not only can you see the price movement over time, with the VIX you can see the nervousness of the market in real time too.   The VXX, being driven by the VIX futures feels more like the medium term view--the trader view, rather than the emotional gauge.

  It would be interesting to know primary and secondary forces driving the moves in VIX on a day like today.  My guess is that the main driver increasing the VIX on nervous/ strongly down days like this is demand for protective puts, and secondarily arbitrage, or just market maker compensation on the call side.  I wonder if anyone has ever figured out how to get data on this topic.          

Closed out VIX vertical spread--expecting fear to increase

The Oct VIX options still have 8 days to live and I expect  the market to have at least a small correction in the next couple of days,  so I decided to cash out of my VIX option spread and take my profits.   Tried debit orders to close out the position, starting at .08.  It finally went at .11.   At fill time the VIX 27.5 had a .20/.25 bid/ask, and the 30 was at 10/20.  The actual fill prices were .24 and .13 respectively.

Given the volatility of volatility (which you should understand if you are going to trade VIX options) I am wondering if in the future, in similar circumstances, if  I should take larger positions and plan a profit exit point that doesn't try to wring so much of the potential profit out of the position.   In this case I only left .11/.75  -- 15% on the table, but exposed myself to substantial risk that the market would go against me.