I use the one part megacrop for vegetative up until half way through flip and then switch to the two part formula.
It's super easy and cheap. Don't have to worry about kelp, chitosan, B vitamins and all that crap through vegetative.
During start of vegetative I start with megacrop one part at about 1.0 EC and up it as needed until it's around 1.6 EC which is usually peak vegetative. I add in epsom as needed.
And then once I flip I go to the two part for more control through flowering. Starting around the same EC, and checking run off.
I do coco DTW, so always adjusting if necessary based off of run off... but the grows generally follow the same EC.
Megacrop just makes it simple and really really cheap. I'd be spending $30-$60 per 55 gallon reservoir depending on what bottled nutrients used... with megacrop it's like $3. If full flower I have to fill that reservoir twice a week.. not happening cost effectively unless I'm using a powdered nute.
Megacrop one part is great for flushing too. Makes it simple to mix up a quick 0.8 - 1.0 EC flush mix when the inevitable build up happens.
Yah, I'm a megafanboy... I paid way too much for water before, and this stuff makes it so cheap and simple. I'll never go back to bottled nutes.