yes that would make it too hot. I don't use synths so I do not have any experience with that but yeah ffof is already kinda hot. Wait for a week or so after the plant(s) recover from the transplant and see how they look. Assuming the plants being moved in are a decent size they will go through the nutes in the ffof in less than a month (which is the usually how long the nutes last in ffof for a plant from seed) and at that point or when you see deficiencies start feeding. You could (probably) do a 1/2 strength dose 2.5 weeks after the transplant an see how the plants react and go from there.