For sure, are you running RDWC? What are you using for waste destruction diluant(s)? Or are you composting?
I used RDWC in the past. It’s an excellent method. Especially when injecting O2 nanobubbles to get DO2 in the 15-20 ppm range with water temp in the low 70’F range - probably the fastest growing and best yielding system I’ve ever seen. Plus, it helps prevent root disease. I’m unaware of anyone injecting O2 nanobubbles for RDWC or DWC, but I’m sure someone is doing it. DM me if you want to discuss. 
For us, DWC or RDWC wouldn’t work because I’m going to run high plant density (1 plant/SF at most) in single and multitier rooms to get six harvests per year per room.
Plus, for RDWC, I am too concerned about whole crop infection, same goes for ebb/flow, NFT, high-pressure aeroponics (HPA), and (insert recirculation method here). We could use UV and chemical sanitizers, but they aren’t 100%. I wouldn’t sleep well with nightmares of hundreds of plants, all with root rot - something I’ve seen with RDWC in a consult I did years ago.
If I could choose any system for the best plant growth, root health, etc., it would be RDWC injecting O2 nanobubbles (15-20 ppm DO2) with HPA nozzles above the water (with O2 nanobubble injection). While HPA with O2 nanobubbles would probably be better than that hybrid system, I would worry too much about dead pumps leading to dead plants.
I’m using O2 nanobubble injection into my batch tanks for each room with a sizeable O2 generator skid to achieve 15-20 ppm DO2 at the drippers. And after reading exciting and surprising new research on CO2 injection (DCO2) on photosynthetic rate, carbon fixation, growth rate, and yield, I plan to test a 95:5 O2:CO2 gas tank mixture.
I’m planning to use Grodan’s newish Grow Block Improved line. But, when they release their new Max line in the US, I plan to switch. The Grow Block Improved line offers improved air porosity, less channeling, more uniform wetting, and better dry back control. The new Max line offers the same benefits but uses a sugar-based ‘green’ binder for the fibers.
For dry back control and to maximize irrigation events per day (and therefore increase growth rate), I’m using blocks, not slabs. For my plant size (max 2-ish feet tall), I’m using ~2.73 L total substrate volume per plant as GBI GR4 (3"x3"x2.5") for veg to fill the cube quicker (veg is ~2 weeks) and GR22.5 (6"x6"x4) for flowering. I’m stacking the GR4 on top of the GR22.5 for flowering, with three 0.5 GPH Netafim psi-compensating drippers per plant. One dripper in the GR4 block and two in the GR22.5 block - all on the upward slope side of the blocks. Flowering will be drip using Acclima VWC sensors from Growlink (calibrated with Grodan’s new 5-prong VWC sensors) to automate irrigation events. Veg will be timer-based ebb/flow.
I don’t know much about RedRock rockwool, except their Pro line seems to be a white-labeled version of VidaWool from Owens Corning. From the VidaWool/RedRed Pro marketing, I like features like the light-blocking plastic wrap and round clone cores. I am considering using VidaWool instead of Grodan. But I first need to send a bunch of questions to VidaWool (w/r/t air porosity, pH, etc.). I like the price point for VidaWool vs. Grodan.
Another option is Cultiline; their RootmaXX blocks look interesting. But I don’t know if they have reliable US distribution, and I assume the cost would be a factor.
If I were to use VidaWool (i.e., RedRock Pro), I would use their Block 40 (4"x4"x2.5") for veg and Block 144 (6"x6"x4") for flowering; providing ~3 L of substrate per plant. I would stack the Block 40 on top of the Block 60.
- VidaWool Block 40 = RedRock Start Block Pro 42/40
- VidaWool Block 144 = RedRock Grow Block Pro 42/40
RedRock’s ‘solo rectangle grow slabs’ are interesting, but I don’t think they’re available in the Pro line.
I’m ordering their round clone cores to see if they fit inside Grodan blocks. If they, I’ll use them instead of Grodan A-OK 1.5" cubes.
One thing that concerns me a little is their pH. Because, unlike Grodan’s GBI blocks which have very little carbonate (neutral pH), @emdub27 wrote the RedRock block has high pH. However, I’m not sure if he was referring to the Pro line or the standard RedRock rockwool (I suspect the latter). The Grodan rep told me we no longer need to acidify the pre-soak water (to neutralize the carbonates) because their mfg process now reduces the carbonates significantly.
But high carbonate in rockwool isn’t a huge issue. All we need to do is acidify the pre-soak solution. I would test the effect of a range of pre-soak solution pH values on the substrate pH (Pour Through and SME) to identify the ideal pH to neutralize the carbonates significantly. I hope VitalWool already did that testing and can suggest a perfect soak pH.