You did mention the reason for a server rack as a matter of circumstance. But if I were to do and really want the Hydropnics part, I’d sell the Server Rack (good price) and buy the cheaper Pallet Racks. The first thing that comes to mind is that it will be easier to plan, pluck, change lights, etc.
Server Racks - you don’t interact with them often, but you will need to with the Hydroponics one.
Also, your setup is too clean. Water will drip, spill, the pebbles will fall. Looks really nice, though.
About 5 years ago, I worked with a Climate Research Scientist friend, growing exotic plants in dutch-buckets, tower aeroponics, and rack mounted red-lit setups to induce Vitamin B-12 (only found in meat, so deficiencies develops in vegetarian) to Spinach trying to produce Super Spinash.