I'm not familiar with the foaming product (sounds interesting) but usually the MG recommended dosage is something obscene, way above what you would want to use on a regular basis. I was recently checking out the granulated product and the recommended dosage there is 20 times greater than what I use for my outdoor succulents on a weekly basis.
Your plants will tolerate and enjoy more fertilizer if they are in the sun. If they are indoors then you want to cut the dose to a fraction of that. Whatever you end up doing, be sure to flush some water out the bottom of the containers every time you water if possible, so the added salt does not build up in there.
If you want to figure out what kind of dosage you are delivering, it's good to have an idea about ppm N.
http://garden.org/ideas/view/A...
Or whatever works for you, but as a starting point I would say try a quarter the dose they recommend for indoor plants, or 1/10 the dose they recommend for outdoor plants, if you want to fertilize regularly. Something like that. I aim for 50 ppm N, which is on the low side, but I deliver it every time I water.
Different plants respond differently but the thing to watch out for is stretching (too much fert and/or too little light). Sometimes the positive difference you see is more in how much they flower or branch, and that tends to be more on the scale of months.
