This is a fantastic thread, tons of great info, i've scanned through it but i think i'm going to have to go back through several times to fully digest all the info here.
I just wanted to quickly report what i have found with my minimal experimentation with fpe's.
I recently made an fpe from a bunch of fan leaves that i had laying around, i could never bring myself to throw them away, and now i'm glad i hung onto them. I filled a 5 gallon bucked 2/3 full with the leaf, poured in a bunch of blackstrap molasses and brown sugar filled it up with water and let is sit, stiring once to twice a day.(no em inoculation) After about 5 days it stopped bubbling, i poured in another cup or so of sugar and it bubbled for about 3 more days. At that point it appeared that the majority of the nutrients in the leaves had been digested. All the plant material had turned brown which i figured meant most of what was left in solid form was cellulose, which wasnt going to break down easily. I started using it on 1 plant, starting at about 10 ml/gal. within 24 hours that plant had dramatically changed, it's color brightened up, the leaves got much shinier and it had new growth all over the place. Over the last couple of weeks i have slowly increased the dilution rate. The last time i watered it was about 2 days ago, at a rate of 30 ml/gal. the next day it had turned MUCH darker green, and the leaf tips have started to turn down, so i'm thinking is about the max dilution rate i should use, but i am going to keep playing with it to see if that is accurate.
I've also tried it on all my other plants ranging from a spider plant to pineapple sage to my Cryptorcoryne wendtii, tiger lotus and other aquatic plants in my aquarium. For the aquatic plants i diluted it 1/1 with water and injected it straight into the aquarium substrate. It turned out it was a little strong for the crypts, their little leaf tips immediately curled down, but nothing died, now they are growing like crazy. The tiger lotus loved it from the start, and it seems that it may have given it some resistance to the snails that have been continuously chewing holes in it's leaves, either that or it's just out growing the damage that the snails are causing.
Anyway, since i've had such fantastic results with that, i'm now working on a fpe batch made from Lamium purpureum (purple deadnettle) flowers, I chose this plant only because it's taken over my flower beds outside. but my hope is that an fpe made from flowers will the perfect nutrient for growing flowers. We'll see. I also have an alfalfa meal fpe in the works, it's only about 2 days in now, but it's looking very good so far.