Epsom salts is really the “go to” for a fast acting fix, best results are seen from it used in a foliar spray. 1tbsp/gal is what’s worked for me. Additionally, it’s worth saying that Epsom salt won’t alter your pH so any of the foliar solution left, I’d give it to the soil. I can be reapplied weekly until the chlorosis has resigned. In most cases 1 foliar with 1 soil drench is ample.
DONT give Magnesium Sulfate if the plant doesn’t need it. Excessive Magnesium will antagonize the uptake of calcium. If you supplement extra calcium, the surplus will mess with potassium and potentially bond with phosphorus making it too unavailable. So realistically, a foliar is the best choice.
I’m a water only guy, but from my experience once the plant has 3-4 internodes its ok to begin feeding. Go with something lite and gentle. Worm castings or fish manure is a solid source.
You can gradually increase the strength based on how the plant looks and had previously responded. Never follow the dosing on any bottle of liquid nutes. Less is more in every case. The olants will show you when they need more.