IF you can, walk through and inspect an existing installation.
Many grocery stores permit civilians to enter the back warehouse. You could well talk your local grocer into letting you provide a free circuit inspection.
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To prevent nasty call-backs you absolutely want to cork up the conduit penetrations. Any idea of wiring light fixtures from vertical penetrations directly above should be dismissed. The lenses will gradually fill with water.
( c.f. the jelly jar thread. )
Figure on EMT and Sealtite runs.
Figure on 3/4 minimum for box penetration. Use PVC for such since it's easier to trim and does not break the insulation. Obviously, provide a bonding jumper across it.
Be sure to provide drainage weep holes at low points in your system.
Treat everything as if it was 'outdoors.'
It gets dark inside and on top... General lighting doesn't cut it.
You'll need a long pilot bit to align your penetrations.
Time can be saved by using 45 degree Sealtite elbows -- sometimes. Most Sealtite runs will be 1/2" linking an integral T-stat relay that is set by the HVAC j-man. I've never encountered a T-stat independently mounted.
Figure on dedicated C/Bs since a tripped breaker is lethal.
The low power motors typically found in most chill boxes have internal protection for overloads. Meaning that the disconnecting means does not require fuses. A motor rated double-pole or triple-pole toggle switch gets it done.
Shun LBs, stay with 4-squares; exception: beauty effects.
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I normally penetrate inside the left side of the condenser assembly from the inside out -- avoiding any seam.
Figure on bonding conductors running everywhere; I use solid.
A suitable scaffold will save labor at the condenser.
Topside, use a battery powered spot lamp.
Good luck.
