Ewc is better applied directly into the soil and watered on.
Mixing it with water beforehand just dilutes it.
Usually when growing with ewc your main factor is pot size, you wanna mix 10-15% ewc in your soil mix and topdress or fertigate with nutes along the way.
If the pot selected is big enough, you won't have to worry about anything but watering it.
If you flower too late and roots established too much, meaning absence of nutrients,
You will run into trouble, even with topdress.
Reason being is organic matter takes time, ewc are readily available for the roots but people forget not all of it is available all the time, it's a slow release approach.
When your growing under lights in a "turbo environment" as i like to call it, better prepare beforehand for these scenarios.