you can't just fertigate as much as you want, regardless of whether it is some sort of magical coco or anything else.
The plant must drink fast enough to allow for it. The substrate must be constituted properly. If your plant isn't drinking down roughly 1/3rd of the water weight between fertigations, you are probably overwatering or increasing risk of problems. If the plants are at all droopy after fully saturating the substrate, that is indicative of a poorly constituted substrate, and double for any multi-fertigation per day method.
you don't choose the volume. you give enough to get the job done. If soilless, which i would expect/assume, the last fertigation should get at least a 10% runoff to avoid buildup. Simply time how long the slowest pot takes to accomplish the task, and that's your run-time. If consistent about repeating after an appropriate dryback, it'll requier a nearly equivalent volume each time.
Also from what i've read, no reason to push beyond 3 fertigations per day. There was no benefit by comparison from an initial study. initial studies are not to be trusted, but in this case... there's definitely a ceiling for the effect and it probably won't vary too much by genotype in this case. Context makes it a bit more trustworthy conclusion
So, with the correct pot size and a plant drinking fast enogh to allow it, it's a great way to do things. Just don't try to force a square peg through a round hole. Definitely don't pick a volume to give based on what your gut tells you. Use a volume that accomplishes the task correctly.