yea I do the same, use some Bat guano, a few times doing flowering (in Veg I repot, and all grow I use a organic soil)
a nice method I use in early flowering (week 2 or so) is to mix the few tea spoons of guano with some fresh soil (a handful or two) and top it with that before watering
next time I do a top dressing (week 4-5 or so) I like to give em a bit of Maerl (oceanic Lime) mixed in with the guano (a small tea spoon)
and I use some molasses (organic black strap) in my water now and then (every 3th time or so)
I also have some liquid guano tea I use if I see a deficiency and of course the Bag of Epsom salt (as most strains I grow and specially under the LEDs love Mg)
I was in the grow store the other day, mainly to get perlite I notice they got a new Plagron product called Bio mix
http://www.dutch-headshop.com/en/bio-supermix-soil-improver-liter-plagron-p-835.html
Bio Supermix is a unique and complete natural fertilizer to improve your soil. This soil improver is balanced and has live bacteria and fungi, vitamins and minerals, spore elements, worms humus and Peru Guano for optimal plant development. Bio Supermix provides a rich soil and increases resistance.
Composition
Bone meal, Feather meal, Peru Guano, natural phosphate, betonite, maerl, basalt, seaweed meal, lava meal.
Solution of organic NPK fertilizer (1-2-0). 1.2% nitrogen total (N) from which 1.2% organic bound nitrogen. 1.6% water-soluble phosphorus pentoxide (P205). 0.35% water-soluble potassium oxide (K20).
will try to use it on my next run and see how it compare to pure Guano (have a good feeling)