[evlatests] 3-bit setup recommendations

[Rick Perley]

    After some discussion with Ken and Vivek, the agreed overheads for 
setting up to observe with the 3-bit samplers are:

    1) Three minutes at the beginning of any SB, to allow the antennas 
to slew to ~30 degrees, where the T304 attenuators will be set.  The 
argument here is that we have yet to establish the power range over 
which the attenuators should be reset (probably 1dB is too fine, and 2dB 
might be about right.  If so, then setting the levels at/near 30 degrees 
will suffice for nearly all bands and elevations). 
    2) Two more minutes for every LO tuning.  For most initial 3-bit 
observing (certainly for wide-band continuum, and wide-band spectral 
line searches), there should be only a single LO tuning per band.

    We think this is sufficiently general, and cautious. 

    If there are counter-arguments, we need to hear them soon!

    Rick