and data reduction.

DEIMOS
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DEIMOS observations were conducted using the 600 groove mm$^{-1}$ grating blazed at 7200 Å and the GG400 blocking filter, with dithering performed to improve sky subtraction. In the initial observing run, we experimented with minimum slit lengths of both 6$''$ and 10$''$, with no significant difference in redshift success rate. In the subsequent DEIMOS observations we settled on a minimum slit width of 8$''$ as a balance between getting the most targets possible on the mask and getting good sky measurements. Data were reduced using a modified version of the DEEP2 pipeline designed to deal with dithered data.

LRIS
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We used the 400 groove mm$^{-1}$ blue grism blazed at 3400 Å and the 400 groove mm$^{-1}$ red grating blazed at 8500 Å, with the D560 dichroic. Our choice of blue grism gives high sensitivity at bluer wavelengths where identifying features are likely to be found for objects with photometric redshifts of $z\sim1.5-3$, while the red coverage allows for the detection of  for some sources out to $z\sim1.6$. The LRIS spectra were reduced using the IRAF-based BOGUS software developed by D. Stern, S. A. Stanford, and A. Bunker, and flux calibrated using observations of standard 