If this is a rebound from a leading diagonal, then I would expect wave [ii] to retrace between 66 - 81% of Wave [i] down. That should yield an SPX price of 1656 - 1670. Time ratio should be an ideal 3-6 days of retrace since it took 10 days to decline.
So far the sharpness of the rebound helps to verify the leading diagonal. Prices need to confirm by tracing a bit higher to the 1656 - 1670 target range.
Interestingly, the decline was a Fibonacci 88.95 (89) points.