Just to note the differences with the OP, he said to use 3:1 ratio of SPX:VIX, and to buy VIX 40 calls. Don't know how VIX correlate with VXX, but that might pu the VXX calls out at 45 or higher (VXX=23.78, VIX=15.62). Even the 40 VXX calls are only .09 now.