To answer your question, it probably does not matter if you feed right away.
I am starting to question the use of molasses, at least in the commonly used doses (1T/gal). The plant makes it's own sugars, it cannot digest, so the sugars are purely to feed the beasties. 1T is a lot of sugar molecules...imagine the 1/2 cup or more that ends up in the medium.
Another consideration is that the mole-asses is a low grade fert (5-1-1?).
Now I have used exactly the nutes you are using, ran out of botanicare and back to the left over FF. When using the SPT with molasses: If you bubble it, or keep any leftovers, the beasties do some metabolizing and the pH can make some serious swings up...be very careful of this...trust me. I also wonder if this (pH rise) does not take place in the soil in the presence of an abundant unnatural food source.
My current bottle was super active when I got it and remained so for a while. It is now completely shot and does not drop pH when first added like it used to. I stopped using it. I now have some Great White. It is very similar, even smells the same (apple cidery/sewer gas). It is expensive, but after shipping for the SPT it is not much different. I mix it with a dilute worm casting tea, cal-mag plus, liquid karma. this is my base that I add the trios to. I skip the trios and water with the dilute base (~200ppm). I quit using the soluables before seeing them through before, and now have a 6 and 8 week headband that one is on Cha-ching and the other is in flush. I think they maybe a little fatter, lots of trichs, we will see on taste. These have the most healthy foliage late in flower...only 1 teaspoon molasses with these two. Lotsa variables so who knows.
Oh and use the downloadable nute chart at 1/2 strength.
