To me, it (the form) all looks basically ok, except for adding the nutes to the MG too soon.

If the soil is still soaking from last watering or flush, you'll have a decision to make. Flush now, or wait till it dries out a bit. If the situation is deteriorating fast, I'd flush the nutes. But if it's a slow, gradual decline...I'd let the soil dry a bit, and flush later. Root rot sucks, big time.