Mel Frank is the true author of the targets of NPK Mg of 100 100 200 60, it's in the Insiders Guide to Cannabis, Figure 9.7
Google HydroBuddy and HydroCal (Java)
MaxiBloom, FloraNova Bloom, FloraMicro and FloraBloom as well as many other formulas can match this target closely, using PH's premixppm Excel spreadsheet, or the above mentioned newer additions to the scene, you can calculate the value of your commercial nutrients, tinker with the numbers of a single or multiple products to approximate this target.
You can also simply plug in your target at least in Hydrobuddy, which will then instruct you what nutrient salts you need, in what g weight you need to add them, it can also help you make your own a and b solution to counter the precipitation issue. Here is a quick example of Mel Franks target using a few of many nutrients salts, some which need to be added to the program later to increase the variety of its choices.
Mel Frank PH Lucas 100 100 200 60
Potassium Nitrate KNO3 1.9 G
Magnesium Nitrate (Hexahydrate) Mg(NO3)2.6H2O 1.631 G
Phosphoric Acid (30%) H3PO4 3.992 G
This is just one quick example, with more salts in the database I believe soon it will be easier to hit closer to the closest formula.