The molasses is 1 TSP per gallon. With the 3 part GH, look in the FAQ and look up nutrient something or other and you should find a GH 3 part formula called the Lucas formula. A fellow over on Over Grow I believe it was, came up with a GH 3 part formula and it is named the Lucas formula and I think literally thousands of people use it to grow MJ in hydro. It is the amounts and all of that you need to use with the 3 part.
If you don't find it in the FAQ I will try to get it somewhere.
Also GH along with Advanced nutes are the only two major US based companies that have openly done consistent research on MJ with there products and that is why they generally seem to be the top choices for many. GH no longer openly does MJ research with their products on MJ and I think that between providing research for places like NASA that they make a little more money with that avenue and do not want to jeopardize there relations by getting into a MJ controversy.
Adieu