I do my math a bit different.
I have a couple old aluminum fuel tanks I removed from a boat in my shop. They both have 1 1/2" fills. I connected the tanks fill nipples together with 1 1/2" hose. I then put a garden hose in one tank full blast from the household pressure in the shop. Since the tanks were cut in half to remove them, I could see the water go from the first tank to the second through the 1 1/2" hose. At full blast the water level in the 1st tank was only about an inch higher than the second the whole time. Even IF I was using the same volume of water (which I'm not), the volume will be flowing through 8 pipes, not just 1. A small water level difference is fine. In fact, it could vary several inches with no effect on the system. I'm thinking of supplying the buckets with solution via a ribbon flow AND a couple spray fittings. A 30 micron filter should keep clogs to a minimum. The return water to res will be under water. To maintain O2 saturation in the res, I'm thinking a second small pump with elevated sprayers blasting the surface with a dozen streams of water.
I like the thinset idea. I'll just dilute the shit out of it with silica sand to prevent a strong bond with the slab (I do need to move out one day).
The T-5 1 system (basically a cloner, but just with an air stone), and the T-5 2 system ( air stoned buckets to a central res) are complete and growing plants. The T-5 2 plants are now touching leaves (after just 6 days!) and need to be moved into the new designed bucket system under 2 1000 watt MH's. This MUST be built tomorrow. Then I just need to keep building one 8 bucket system at a time to keep recieving plants as older plants are harvested from bloom. In about 10 weeks, the whole op will be 100% DWC. I've started the flush on our first 2 DWC plants today...known as Godzilla and his buddy. From previous experience, this flush will take less than a week, as opposed to 2.5 weeks with the coco. I'm really looking forward to the final yield results of these 2 plants, as they are the exact sized plants I can grow to fill out the room and stay under our plants limit. Up until now, we've been kind of "freestyle" with any total yield calculations. Now, we can start fine tuning and pumping up the yield over this summer. Once the DWC is perfect, it will be time to seal the rooms, add the ductless A/C system, and fire up the CO2. Play time is over. It's time to get serious. Helper D's job is about to kick into overdrive.